diff --git a/didier/cogs/currency.py b/didier/cogs/currency.py
index 709a461..4049654 100644
--- a/didier/cogs/currency.py
+++ b/didier/cogs/currency.py
@@ -25,7 +25,7 @@ class Currency(commands.Cog):
         super().__init__()
         self.client = client
 
-    @commands.command(name="award")
+    @commands.command(name="award")  # type: ignore[arg-type]
     @commands.check(is_owner)
     async def award(
         self,
@@ -49,7 +49,9 @@ class Currency(commands.Cog):
             bank = await crud.get_bank(session, ctx.author.id)
 
         embed = discord.Embed(title=f"{ctx.author.display_name}'s Bank", colour=discord.Colour.blue())
-        embed.set_thumbnail(url=ctx.author.avatar.url)
+
+        if ctx.author.avatar is not None:
+            embed.set_thumbnail(url=ctx.author.avatar.url)
 
         embed.add_field(name="Interest level", value=bank.interest_level)
         embed.add_field(name="Capacity level", value=bank.capacity_level)
@@ -57,7 +59,9 @@ class Currency(commands.Cog):
 
         await ctx.reply(embed=embed, mention_author=False)
 
-    @bank.group(name="upgrade", aliases=["u", "upgrades"], case_insensitive=True, invoke_without_command=True)
+    @bank.group(  # type: ignore[arg-type]
+        name="upgrade", aliases=["u", "upgrades"], case_insensitive=True, invoke_without_command=True
+    )
     async def bank_upgrades(self, ctx: commands.Context):
         """List the upgrades you can buy & their prices."""
         async with self.client.postgres_session as session:
@@ -77,7 +81,7 @@ class Currency(commands.Cog):
 
         await ctx.reply(embed=embed, mention_author=False)
 
-    @bank_upgrades.command(name="capacity", aliases=["c"])
+    @bank_upgrades.command(name="capacity", aliases=["c"])  # type: ignore[arg-type]
     async def bank_upgrade_capacity(self, ctx: commands.Context):
         """Upgrade the capacity level of your bank."""
         async with self.client.postgres_session as session:
@@ -88,7 +92,7 @@ class Currency(commands.Cog):
                 await ctx.reply("You don't have enough Didier Dinks to do this.", mention_author=False)
                 await self.client.reject_message(ctx.message)
 
-    @bank_upgrades.command(name="interest", aliases=["i"])
+    @bank_upgrades.command(name="interest", aliases=["i"])  # type: ignore[arg-type]
     async def bank_upgrade_interest(self, ctx: commands.Context):
         """Upgrade the interest level of your bank."""
         async with self.client.postgres_session as session:
@@ -99,7 +103,7 @@ class Currency(commands.Cog):
                 await ctx.reply("You don't have enough Didier Dinks to do this.", mention_author=False)
                 await self.client.reject_message(ctx.message)
 
-    @bank_upgrades.command(name="rob", aliases=["r"])
+    @bank_upgrades.command(name="rob", aliases=["r"])  # type: ignore[arg-type]
     async def bank_upgrade_rob(self, ctx: commands.Context):
         """Upgrade the rob level of your bank."""
         async with self.client.postgres_session as session:
@@ -110,7 +114,7 @@ class Currency(commands.Cog):
                 await ctx.reply("You don't have enough Didier Dinks to do this.", mention_author=False)
                 await self.client.reject_message(ctx.message)
 
-    @commands.hybrid_command(name="dinks")
+    @commands.hybrid_command(name="dinks")  # type: ignore[arg-type]
     async def dinks(self, ctx: commands.Context):
         """Check your Didier Dinks."""
         async with self.client.postgres_session as session:
@@ -118,7 +122,7 @@ class Currency(commands.Cog):
             plural = pluralize("Didier Dink", bank.dinks)
             await ctx.reply(f"**{ctx.author.display_name}** has **{bank.dinks}** {plural}.", mention_author=False)
 
-    @commands.command(name="invest", aliases=["deposit", "dep"])
+    @commands.command(name="invest", aliases=["deposit", "dep"])  # type: ignore[arg-type]
     async def invest(self, ctx: commands.Context, amount: typing.Annotated[typing.Union[str, int], abbreviated_number]):
         """Invest `amount` Didier Dinks into your bank.
 
@@ -144,7 +148,7 @@ class Currency(commands.Cog):
                     f"**{ctx.author.display_name}** has invested **{invested}** {plural}.", mention_author=False
                 )
 
-    @commands.hybrid_command(name="nightly")
+    @commands.hybrid_command(name="nightly")  # type: ignore[arg-type]
     async def nightly(self, ctx: commands.Context):
         """Claim nightly Didier Dinks."""
         async with self.client.postgres_session as session:
diff --git a/didier/cogs/debug_cog.py b/didier/cogs/debug_cog.py
index 2d03b9f..a0e4747 100644
--- a/didier/cogs/debug_cog.py
+++ b/didier/cogs/debug_cog.py
@@ -13,7 +13,7 @@ class DebugCog(commands.Cog):
         self.client = client
 
     @overrides
-    async def cog_check(self, ctx: commands.Context) -> bool:
+    async def cog_check(self, ctx: commands.Context) -> bool:  # type:ignore[override]
         return await self.client.is_owner(ctx.author)
 
     @commands.command(aliases=["Dev"])
diff --git a/didier/cogs/discord.py b/didier/cogs/discord.py
index eaf0179..fdfa05d 100644
--- a/didier/cogs/discord.py
+++ b/didier/cogs/discord.py
@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Optional, Union, cast
 
 import discord
 from discord import app_commands
@@ -17,6 +17,7 @@ from didier.exceptions import expect
 from didier.menus.bookmarks import BookmarkSource
 from didier.utils.discord import colours
 from didier.utils.discord.assets import get_author_avatar, get_user_avatar
+from didier.utils.discord.channels import NON_MESSAGEABLE_CHANNEL_TYPES
 from didier.utils.discord.constants import Limits
 from didier.utils.timer import Timer
 from didier.utils.types.datetime import localize, str_to_date, tz_aware_now
@@ -60,9 +61,19 @@ class Discord(commands.Cog):
             event = await events.get_event_by_id(session, event_id)
 
             if event is None:
-                return await self.client.log_error(f"Unable to find event with id {event_id}", log_to_discord=True)
+                return await self.client.log_error(f"Unable to find event with id {event_id}.", log_to_discord=True)
 
             channel = self.client.get_channel(event.notification_channel)
+            if channel is None:
+                return await self.client.log_error(
+                    f"Unable to fetch channel for event `#{event_id}` (id `{event.notification_channel}`)."
+                )
+
+            if isinstance(channel, NON_MESSAGEABLE_CHANNEL_TYPES):
+                return await self.client.log_error(
+                    f"Channel for event `#{event_id}` (id `{event.notification_channel}`) is not messageable."
+                )
+
             human_readable_time = localize(event.timestamp).strftime("%A, %B %d %Y - %H:%M")
 
             embed = discord.Embed(title=event.name, colour=discord.Colour.blue())
@@ -81,7 +92,7 @@ class Discord(commands.Cog):
         self.client.loop.create_task(self.timer.update())
 
     @commands.group(name="birthday", aliases=["bd", "birthdays"], case_insensitive=True, invoke_without_command=True)
-    async def birthday(self, ctx: commands.Context, user: discord.User = None):
+    async def birthday(self, ctx: commands.Context, user: Optional[discord.User] = None):
         """Command to check the birthday of `user`.
 
         Not passing an argument for `user` will show yours instead.
@@ -98,8 +109,10 @@ class Discord(commands.Cog):
         day, month = leading("0", str(birthday.birthday.day)), leading("0", str(birthday.birthday.month))
         return await ctx.reply(f"{name or 'Your'} birthday is set to **{day}/{month}**.", mention_author=False)
 
-    @birthday.command(name="set", aliases=["config"])
-    async def birthday_set(self, ctx: commands.Context, day: str, user: Optional[discord.User] = None):
+    @birthday.command(name="set", aliases=["config"])  # type: ignore[arg-type]
+    async def birthday_set(
+        self, ctx: commands.Context, day: str, user: Optional[Union[discord.User, discord.Member]] = None
+    ):
         """Set your birthday to `day`.
 
         Parsing of the `day`-argument happens in the following order: `DD/MM/YYYY`, `DD/MM/YY`, `DD/MM`.
@@ -113,6 +126,9 @@ class Discord(commands.Cog):
         if user is None:
             user = ctx.author
 
+        # Please Mypy
+        user = cast(Union[discord.User, discord.Member], user)
+
         try:
             default_year = 2001
             date = str_to_date(day, formats=["%d/%m/%Y", "%d/%m/%y", "%d/%m"])
@@ -141,7 +157,7 @@ class Discord(commands.Cog):
         """
         # No label: shortcut to display bookmarks
         if label is None:
-            return await self.bookmark_search(ctx, query=None)
+            return await self.bookmark_search(ctx, query=None)  # type: ignore[arg-type]
 
         async with self.client.postgres_session as session:
             result = expect(
@@ -151,7 +167,7 @@ class Discord(commands.Cog):
             )
             await ctx.reply(result.jump_url, mention_author=False)
 
-    @bookmark.command(name="create", aliases=["new"])
+    @bookmark.command(name="create", aliases=["new"])  # type: ignore[arg-type]
     async def bookmark_create(self, ctx: commands.Context, label: str, message: Optional[discord.Message]):
         """Create a new bookmark for message `message` with label `label`.
 
@@ -182,7 +198,7 @@ class Discord(commands.Cog):
             # Label isn't allowed
             return await ctx.reply(f"Bookmarks cannot be named `{label}`.", mention_author=False)
 
-    @bookmark.command(name="delete", aliases=["rm"])
+    @bookmark.command(name="delete", aliases=["rm"])  # type: ignore[arg-type]
     async def bookmark_delete(self, ctx: commands.Context, bookmark_id: str):
         """Delete the bookmark with id `bookmark_id`.
 
@@ -207,7 +223,7 @@ class Discord(commands.Cog):
 
         return await ctx.reply(f"Successfully deleted bookmark `#{bookmark_id_int}`.", mention_author=False)
 
-    @bookmark.command(name="search", aliases=["list", "ls"])
+    @bookmark.command(name="search", aliases=["list", "ls"])  # type: ignore[arg-type]
     async def bookmark_search(self, ctx: commands.Context, *, query: Optional[str] = None):
         """Search through the list of bookmarks.
 
@@ -236,7 +252,7 @@ class Discord(commands.Cog):
         modal = CreateBookmark(self.client, message.jump_url)
         await interaction.response.send_modal(modal)
 
-    @commands.hybrid_command(name="events")
+    @commands.hybrid_command(name="events")  # type: ignore[arg-type]
     @app_commands.rename(event_id="id")
     @app_commands.describe(event_id="The id of the event to fetch. If not passed, all events are fetched instead.")
     async def events(self, ctx: commands.Context, event_id: Optional[int] = None):
@@ -276,16 +292,16 @@ class Discord(commands.Cog):
                     embed.add_field(
                         name="Timer", value=discord.utils.format_dt(result_event.timestamp, style="R"), inline=True
                     )
-                    embed.add_field(
-                        name="Channel",
-                        value=self.client.get_channel(result_event.notification_channel).mention,
-                        inline=False,
-                    )
+
+                    channel = self.client.get_channel(result_event.notification_channel)
+                    if channel is not None and not isinstance(channel, NON_MESSAGEABLE_CHANNEL_TYPES):
+                        embed.add_field(name="Channel", value=channel.mention, inline=False)
+
                     embed.description = result_event.description
                     return await ctx.reply(embed=embed, mention_author=False)
 
     @commands.group(name="github", aliases=["gh", "git"], case_insensitive=True, invoke_without_command=True)
-    async def github_group(self, ctx: commands.Context, user: Optional[discord.User] = None):
+    async def github_group(self, ctx: commands.Context, user: Optional[Union[discord.User, discord.Member]] = None):
         """Show a user's GitHub links.
 
         If no user is provided, this shows your links instead.
@@ -293,6 +309,9 @@ class Discord(commands.Cog):
         # Default to author
         user = user or ctx.author
 
+        # Please Mypy
+        user = cast(Union[discord.User, discord.Member], user)
+
         embed = discord.Embed(colour=colours.github_white(), title="GitHub Links")
         embed.set_author(name=user.display_name, icon_url=get_user_avatar(user))
 
@@ -324,7 +343,7 @@ class Discord(commands.Cog):
 
         return await ctx.reply(embed=embed, mention_author=False)
 
-    @github_group.command(name="add", aliases=["create", "insert"])
+    @github_group.command(name="add", aliases=["create", "insert"])  # type: ignore[arg-type]
     async def github_add(self, ctx: commands.Context, link: str):
         """Add a new link into the database."""
         # Remove wrapping <brackets> which can be used to escape Discord embeds
@@ -339,7 +358,7 @@ class Discord(commands.Cog):
         await self.client.confirm_message(ctx.message)
         return await ctx.reply(f"Successfully inserted link `#{gh_link.github_link_id}`.", mention_author=False)
 
-    @github_group.command(name="delete", aliases=["del", "remove", "rm"])
+    @github_group.command(name="delete", aliases=["del", "remove", "rm"])  # type: ignore[arg-type]
     async def github_delete(self, ctx: commands.Context, link_id: str):
         """Delete the link with it `link_id` from the database.
 
@@ -411,7 +430,7 @@ class Discord(commands.Cog):
         await message.add_reaction("📌")
         return await interaction.response.send_message("📌", ephemeral=True)
 
-    @commands.hybrid_command(name="snipe")
+    @commands.hybrid_command(name="snipe")  # type: ignore[arg-type]
     async def snipe(self, ctx: commands.Context):
         """Publicly shame people when they edit or delete one of their messages.
 
diff --git a/didier/cogs/fun.py b/didier/cogs/fun.py
index e824ab2..4ccfb2a 100644
--- a/didier/cogs/fun.py
+++ b/didier/cogs/fun.py
@@ -28,7 +28,7 @@ class Fun(commands.Cog):
     def __init__(self, client: Didier):
         self.client = client
 
-    @commands.hybrid_command(name="clap")
+    @commands.hybrid_command(name="clap")  # type: ignore[arg-type]
     async def clap(self, ctx: commands.Context, *, text: str):
         """Clap a message with emojis for extra dramatic effect"""
         chars = list(filter(lambda c: c in constants.EMOJI_MAP, text))
@@ -50,10 +50,7 @@ class Fun(commands.Cog):
             meme = await generate_meme(self.client.http_session, result, fields)
             return meme
 
-    @commands.hybrid_command(
-        name="dadjoke",
-        aliases=["dad", "dj"],
-    )
+    @commands.hybrid_command(name="dadjoke", aliases=["dad", "dj"])  # type: ignore[arg-type]
     async def dad_joke(self, ctx: commands.Context):
         """Why does Yoda's code always crash? Because there is no try."""
         async with self.client.postgres_session as session:
@@ -83,13 +80,13 @@ class Fun(commands.Cog):
             return await self.memegen_ls_msg(ctx)
 
         if fields is None:
-            return await self.memegen_preview_msg(ctx, template)
+            return await self.memegen_preview_msg(ctx, template)  # type: ignore[arg-type]
 
         async with ctx.typing():
             meme = await self._do_generate_meme(template, shlex.split(fields))
             return await ctx.reply(meme, mention_author=False)
 
-    @memegen_msg.command(name="list", aliases=["ls"])
+    @memegen_msg.command(name="list", aliases=["ls"])  # type: ignore[arg-type]
     async def memegen_ls_msg(self, ctx: commands.Context):
         """Get a list of all available meme templates.
 
@@ -100,14 +97,14 @@ class Fun(commands.Cog):
 
         await MemeSource(ctx, results).start()
 
-    @memegen_msg.command(name="preview", aliases=["p"])
+    @memegen_msg.command(name="preview", aliases=["p"])  # type: ignore[arg-type]
     async def memegen_preview_msg(self, ctx: commands.Context, template: str):
         """Generate a preview for the meme template `template`, to see how the fields are structured."""
         async with ctx.typing():
             meme = await self._do_generate_meme(template, [])
             return await ctx.reply(meme, mention_author=False)
 
-    @memes_slash.command(name="generate")
+    @memes_slash.command(name="generate")  # type: ignore[arg-type]
     async def memegen_slash(self, interaction: discord.Interaction, template: str):
         """Generate a meme."""
         async with self.client.postgres_session as session:
@@ -116,7 +113,7 @@ class Fun(commands.Cog):
         modal = GenerateMeme(self.client, result)
         await interaction.response.send_modal(modal)
 
-    @memes_slash.command(name="preview")
+    @memes_slash.command(name="preview")  # type: ignore[arg-type]
     @app_commands.describe(template="The meme template to use in the preview.")
     async def memegen_preview_slash(self, interaction: discord.Interaction, template: str):
         """Generate a preview for a meme, to see how the fields are structured."""
@@ -134,7 +131,7 @@ class Fun(commands.Cog):
         """Autocompletion for the 'template'-parameter"""
         return self.client.database_caches.memes.get_autocomplete_suggestions(current)
 
-    @app_commands.command()
+    @app_commands.command()  # type: ignore[arg-type]
     @app_commands.describe(message="The text to convert.")
     async def mock(self, interaction: discord.Interaction, message: str):
         """Mock a message.
@@ -158,7 +155,7 @@ class Fun(commands.Cog):
 
         return await interaction.followup.send(mock(message))
 
-    @commands.hybrid_command(name="xkcd")
+    @commands.hybrid_command(name="xkcd")  # type: ignore[arg-type]
     @app_commands.rename(comic_id="id")
     async def xkcd(self, ctx: commands.Context, comic_id: Optional[int] = None):
         """Fetch comic `#id` from xkcd.
diff --git a/didier/cogs/help.py b/didier/cogs/help.py
index ddb568d..57cad6d 100644
--- a/didier/cogs/help.py
+++ b/didier/cogs/help.py
@@ -159,6 +159,9 @@ class CustomHelpCommand(commands.MinimalHelpCommand):
         Code in codeblocks is ignored, as it is used to create examples.
         """
         description = command.help
+        if description is None:
+            return ""
+
         codeblocks = re_find_all(r"\n?```.*?```", description, flags=re.DOTALL)
 
         # Regex borrowed from https://stackoverflow.com/a/59843498/13568999
@@ -198,13 +201,10 @@ class CustomHelpCommand(commands.MinimalHelpCommand):
 
         return None
 
-    async def _filter_cogs(self, cogs: list[commands.Cog]) -> list[commands.Cog]:
+    async def _filter_cogs(self, cogs: list[Optional[commands.Cog]]) -> list[commands.Cog]:
         """Filter the list of cogs down to all those that the user can see"""
 
-        async def _predicate(cog: Optional[commands.Cog]) -> bool:
-            if cog is None:
-                return False
-
+        async def _predicate(cog: commands.Cog) -> bool:
             # Remove cogs that we never want to see in the help page because they
             # don't contain commands, or shouldn't be visible at all
             if not cog.get_commands():
@@ -220,7 +220,7 @@ class CustomHelpCommand(commands.MinimalHelpCommand):
             return True
 
         # Filter list of cogs down
-        filtered_cogs = [cog for cog in cogs if await _predicate(cog)]
+        filtered_cogs = [cog for cog in cogs if cog is not None and await _predicate(cog)]
         return list(sorted(filtered_cogs, key=lambda cog: cog.qualified_name))
 
     def _get_flags_class(self, command: commands.Command) -> Optional[Type[PosixFlags]]:
diff --git a/didier/cogs/meta.py b/didier/cogs/meta.py
index c330dbd..861bf58 100644
--- a/didier/cogs/meta.py
+++ b/didier/cogs/meta.py
@@ -1,6 +1,6 @@
 import inspect
 import os
-from typing import Optional
+from typing import Any, Optional, Union
 
 from discord.ext import commands
 
@@ -76,18 +76,24 @@ class Meta(commands.Cog):
         if command_name is None:
             return await ctx.reply(repo_home, mention_author=False)
 
+        command: Optional[Union[commands.HelpCommand, commands.Command]]
+        src: Any
+
         if command_name == "help":
             command = self.client.help_command
+            if command is None:
+                return await ctx.reply(f"Found no command named `{command_name}`.", mention_author=False)
+
             src = type(self.client.help_command)
             filename = inspect.getsourcefile(src)
         else:
             command = self.client.get_command(command_name)
+            if command is None:
+                return await ctx.reply(f"Found no command named `{command_name}`.", mention_author=False)
+
             src = command.callback.__code__
             filename = src.co_filename
 
-        if command is None:
-            return await ctx.reply(f"Found no command named `{command_name}`.", mention_author=False)
-
         lines, first_line = inspect.getsourcelines(src)
 
         if filename is None:
diff --git a/didier/cogs/other.py b/didier/cogs/other.py
index 02c0095..a48cb5e 100644
--- a/didier/cogs/other.py
+++ b/didier/cogs/other.py
@@ -22,7 +22,7 @@ class Other(commands.Cog):
     def __init__(self, client: Didier):
         self.client = client
 
-    @commands.hybrid_command(name="corona", aliases=["covid", "rona"])
+    @commands.hybrid_command(name="corona", aliases=["covid", "rona"])  # type: ignore[arg-type]
     async def covid(self, ctx: commands.Context, country: str = "Belgium"):
         """Show Covid-19 info for a specific country.
 
@@ -43,7 +43,7 @@ class Other(commands.Cog):
         """Autocompletion for the 'country'-parameter"""
         return autocomplete_country(value)[:25]
 
-    @commands.hybrid_command(
+    @commands.hybrid_command(  # type: ignore[arg-type]
         name="define", aliases=["ud", "urban"], description="Look up the definition of a word on the Urban Dictionary"
     )
     async def define(self, ctx: commands.Context, *, query: str):
@@ -55,7 +55,7 @@ class Other(commands.Cog):
                 mention_author=False,
             )
 
-    @commands.hybrid_command(name="google", description="Google search")
+    @commands.hybrid_command(name="google", description="Google search")  # type: ignore[arg-type]
     @app_commands.describe(query="Search query")
     async def google(self, ctx: commands.Context, *, query: str):
         """Show the Google search results for `query`.
@@ -71,7 +71,7 @@ class Other(commands.Cog):
             embed = GoogleSearch(results).to_embed()
             await ctx.reply(embed=embed, mention_author=False)
 
-    @commands.hybrid_command(name="inspire", description="Generate an InspiroBot quote.")
+    @commands.hybrid_command(name="inspire", description="Generate an InspiroBot quote.")  # type: ignore[arg-type]
     async def inspire(self, ctx: commands.Context):
         """Generate an [InspiroBot](https://inspirobot.me/) quote."""
         async with ctx.typing():
@@ -82,7 +82,7 @@ class Other(commands.Cog):
         async with self.client.postgres_session as session:
             return await get_link_by_name(session, name.lower())
 
-    @commands.command(name="Link", aliases=["Links"])
+    @commands.command(name="Link", aliases=["Links"])  # type: ignore[arg-type]
     async def link_msg(self, ctx: commands.Context, name: str):
         """Get the link to the resource named `name`."""
         link = await self._get_link(name)
@@ -92,7 +92,7 @@ class Other(commands.Cog):
         target_message = await self.client.get_reply_target(ctx)
         await target_message.reply(link.url, mention_author=False)
 
-    @app_commands.command(name="link")
+    @app_commands.command(name="link")  # type: ignore[arg-type]
     @app_commands.describe(name="The name of the resource")
     async def link_slash(self, interaction: discord.Interaction, name: str):
         """Get the link to something."""
diff --git a/didier/cogs/owner.py b/didier/cogs/owner.py
index 139f02c..1f72eff 100644
--- a/didier/cogs/owner.py
+++ b/didier/cogs/owner.py
@@ -42,7 +42,7 @@ class Owner(commands.Cog):
     def __init__(self, client: Didier):
         self.client = client
 
-    async def cog_check(self, ctx: commands.Context) -> bool:
+    async def cog_check(self, ctx: commands.Context) -> bool:  # type: ignore[override]
         """Global check for every command in this cog
 
         This means that we don't have to add is_owner() to every single command separately
@@ -102,7 +102,7 @@ class Owner(commands.Cog):
     async def add_msg(self, ctx: commands.Context):
         """Command group for [add X] message commands"""
 
-    @add_msg.command(name="Alias")
+    @add_msg.command(name="Alias")  # type: ignore[arg-type]
     async def add_alias_msg(self, ctx: commands.Context, command: str, alias: str):
         """Add a new alias for a custom command"""
         async with self.client.postgres_session as session:
@@ -116,7 +116,7 @@ class Owner(commands.Cog):
                 await ctx.reply("There is already a command with this name.")
                 await self.client.reject_message(ctx.message)
 
-    @add_msg.command(name="Custom")
+    @add_msg.command(name="Custom")  # type: ignore[arg-type]
     async def add_custom_msg(self, ctx: commands.Context, name: str, *, response: str):
         """Add a new custom command"""
         async with self.client.postgres_session as session:
@@ -127,7 +127,7 @@ class Owner(commands.Cog):
                 await ctx.reply("There is already a command with this name.")
                 await self.client.reject_message(ctx.message)
 
-    @add_msg.command(name="Link")
+    @add_msg.command(name="Link")  # type: ignore[arg-type]
     async def add_link_msg(self, ctx: commands.Context, name: str, url: str):
         """Add a new link"""
         async with self.client.postgres_session as session:
@@ -136,7 +136,7 @@ class Owner(commands.Cog):
 
         await self.client.confirm_message(ctx.message)
 
-    @add_slash.command(name="custom", description="Add a custom command")
+    @add_slash.command(name="custom", description="Add a custom command")  # type: ignore[arg-type]
     async def add_custom_slash(self, interaction: discord.Interaction):
         """Slash command to add a custom command"""
         if not await self.client.is_owner(interaction.user):
@@ -145,7 +145,7 @@ class Owner(commands.Cog):
         modal = CreateCustomCommand(self.client)
         await interaction.response.send_modal(modal)
 
-    @add_slash.command(name="dadjoke", description="Add a dad joke")
+    @add_slash.command(name="dadjoke", description="Add a dad joke")  # type: ignore[arg-type]
     async def add_dad_joke_slash(self, interaction: discord.Interaction):
         """Slash command to add a dad joke"""
         if not await self.client.is_owner(interaction.user):
@@ -154,7 +154,7 @@ class Owner(commands.Cog):
         modal = AddDadJoke(self.client)
         await interaction.response.send_modal(modal)
 
-    @add_slash.command(name="deadline", description="Add a deadline")
+    @add_slash.command(name="deadline", description="Add a deadline")  # type: ignore[arg-type]
     @app_commands.describe(course="The name of the course to add a deadline for (aliases work too)")
     async def add_deadline_slash(self, interaction: discord.Interaction, course: str):
         """Slash command to add a deadline"""
@@ -174,7 +174,7 @@ class Owner(commands.Cog):
         """Autocompletion for the 'course'-parameter"""
         return self.client.database_caches.ufora_courses.get_autocomplete_suggestions(current)
 
-    @add_slash.command(name="event", description="Add a new event")
+    @add_slash.command(name="event", description="Add a new event")  # type: ignore[arg-type]
     async def add_event_slash(self, interaction: discord.Interaction):
         """Slash command to add new events"""
         if not await self.client.is_owner(interaction.user):
@@ -183,7 +183,7 @@ class Owner(commands.Cog):
         modal = AddEvent(self.client)
         await interaction.response.send_modal(modal)
 
-    @add_slash.command(name="link", description="Add a new link")
+    @add_slash.command(name="link", description="Add a new link")  # type: ignore[arg-type]
     async def add_link_slash(self, interaction: discord.Interaction):
         """Slash command to add new links"""
         if not await self.client.is_owner(interaction.user):
@@ -192,7 +192,7 @@ class Owner(commands.Cog):
         modal = AddLink(self.client)
         await interaction.response.send_modal(modal)
 
-    @add_slash.command(name="meme", description="Add a new meme")
+    @add_slash.command(name="meme", description="Add a new meme")  # type: ignore[arg-type]
     async def add_meme_slash(self, interaction: discord.Interaction, name: str, imgflip_id: int, field_count: int):
         """Slash command to add new memes"""
         await interaction.response.defer(ephemeral=True)
@@ -205,11 +205,11 @@ class Owner(commands.Cog):
             await interaction.followup.send(f"Added meme `{meme.meme_id}`.")
             await self.client.database_caches.memes.invalidate(session)
 
-    @commands.group(name="Edit", case_insensitive=True, invoke_without_command=False)
+    @commands.group(name="Edit", case_insensitive=True, invoke_without_command=False)  # type: ignore[arg-type]
     async def edit_msg(self, ctx: commands.Context):
         """Command group for [edit X] commands"""
 
-    @edit_msg.command(name="Custom")
+    @edit_msg.command(name="Custom")  # type: ignore[arg-type]
     async def edit_custom_msg(self, ctx: commands.Context, command: str, *, flags: EditCustomFlags):
         """Edit an existing custom command"""
         async with self.client.postgres_session as session:
@@ -220,7 +220,7 @@ class Owner(commands.Cog):
                 await ctx.reply(f"No command found matching `{command}`.")
                 return await self.client.reject_message(ctx.message)
 
-    @edit_slash.command(name="custom", description="Edit a custom command")
+    @edit_slash.command(name="custom", description="Edit a custom command")  # type: ignore[arg-type]
     @app_commands.describe(command="The name of the command to edit")
     async def edit_custom_slash(self, interaction: discord.Interaction, command: str):
         """Slash command to edit a custom command"""
diff --git a/didier/cogs/school.py b/didier/cogs/school.py
index 7af8a81..cd9366a 100644
--- a/didier/cogs/school.py
+++ b/didier/cogs/school.py
@@ -27,7 +27,7 @@ class School(commands.Cog):
     def __init__(self, client: Didier):
         self.client = client
 
-    @commands.hybrid_command(name="deadlines")
+    @commands.hybrid_command(name="deadlines")  # type: ignore[arg-type]
     async def deadlines(self, ctx: commands.Context):
         """Show upcoming deadlines."""
         async with ctx.typing():
@@ -40,7 +40,7 @@ class School(commands.Cog):
             embed = Deadlines(deadlines).to_embed()
             await ctx.reply(embed=embed, mention_author=False, ephemeral=False)
 
-    @commands.hybrid_command(name="les", aliases=["sched", "schedule"])
+    @commands.hybrid_command(name="les", aliases=["sched", "schedule"])  # type: ignore[arg-type]
     @app_commands.rename(day_dt="date")
     async def les(
         self, ctx: commands.Context, *, day_dt: Optional[app_commands.Transform[date, DateTransformer]] = None
@@ -72,10 +72,7 @@ class School(commands.Cog):
             except NotInMainGuildException:
                 return await ctx.reply(f"You are not a member of {self.client.main_guild.name}.", mention_author=False)
 
-    @commands.hybrid_command(
-        name="menu",
-        aliases=["eten", "food"],
-    )
+    @commands.hybrid_command(name="menu", aliases=["eten", "food"])  # type: ignore[arg-type]
     @app_commands.rename(day_dt="date")
     async def menu(
         self, ctx: commands.Context, *, day_dt: Optional[app_commands.Transform[date, DateTransformer]] = None
@@ -96,7 +93,7 @@ class School(commands.Cog):
                 embed = no_menu_found(day_dt)
             await ctx.reply(embed=embed, mention_author=False)
 
-    @commands.hybrid_command(
+    @commands.hybrid_command(  # type: ignore[arg-type]
         name="fiche", description="Sends the link to study guides", aliases=["guide", "studiefiche"]
     )
     @app_commands.describe(course="The name of the course to fetch the study guide for (aliases work too)")
@@ -124,7 +121,7 @@ class School(commands.Cog):
             mention_author=False,
         )
 
-    @commands.hybrid_command(name="ufora")
+    @commands.hybrid_command(name="ufora")  # type: ignore[arg-type]
     async def ufora(self, ctx: commands.Context, course: str):
         """Link the Ufora page for a course."""
         async with self.client.postgres_session as session:
diff --git a/didier/cogs/tasks.py b/didier/cogs/tasks.py
index 07d6508..f59d697 100644
--- a/didier/cogs/tasks.py
+++ b/didier/cogs/tasks.py
@@ -1,4 +1,6 @@
+import asyncio
 import datetime
+import logging
 import random
 
 import discord
@@ -20,9 +22,12 @@ from didier.data.embeds.schedules import (
 from didier.data.rss_feeds.free_games import fetch_free_games
 from didier.data.rss_feeds.ufora import fetch_ufora_announcements
 from didier.decorators.tasks import timed_task
+from didier.utils.discord.channels import NON_MESSAGEABLE_CHANNEL_TYPES
 from didier.utils.discord.checks import is_owner
 from didier.utils.types.datetime import LOCAL_TIMEZONE, tz_aware_now
 
+logger = logging.getLogger(__name__)
+
 # datetime.time()-instances for when every task should run
 DAILY_RESET_TIME = datetime.time(hour=0, minute=0, tzinfo=LOCAL_TIMEZONE)
 SOCIALLY_ACCEPTABLE_TIME = datetime.time(hour=7, minute=0, tzinfo=LOCAL_TIMEZONE)
@@ -56,7 +61,7 @@ class Tasks(commands.Cog):
         }
 
     @overrides
-    def cog_load(self) -> None:
+    async def cog_load(self) -> None:
         # Only check birthdays if there's a channel to send it to
         if settings.BIRTHDAY_ANNOUNCEMENT_CHANNEL is not None:
             self.check_birthdays.start()
@@ -72,9 +77,10 @@ class Tasks(commands.Cog):
 
         # Start other tasks
         self.reminders.start()
+        asyncio.create_task(self.get_error_channel())
 
     @overrides
-    def cog_unload(self) -> None:
+    async def cog_unload(self) -> None:
         # Cancel all pending tasks
         for task in self._tasks.values():
             if task.is_running():
@@ -96,7 +102,7 @@ class Tasks(commands.Cog):
 
         await ctx.reply(embed=embed, mention_author=False)
 
-    @tasks_group.command(name="Force", case_insensitive=True, usage="[Task]")
+    @tasks_group.command(name="Force", case_insensitive=True, usage="[Task]")  # type: ignore[arg-type]
     async def force_task(self, ctx: commands.Context, name: str):
         """Command to force-run a task without waiting for the specified run time"""
         name = name.lower()
@@ -107,23 +113,53 @@ class Tasks(commands.Cog):
         await task(forced=True)
         await self.client.confirm_message(ctx.message)
 
+    async def get_error_channel(self):
+        """Get the configured channel from the cache"""
+        await self.client.wait_until_ready()
+
+        # Configure channel to send errors to
+        if settings.ERRORS_CHANNEL is not None:
+            channel = self.client.get_channel(settings.ERRORS_CHANNEL)
+
+            if isinstance(channel, NON_MESSAGEABLE_CHANNEL_TYPES):
+                logger.error(f"Configured error channel (id `{settings.ERRORS_CHANNEL}`) is not messageable.")
+            else:
+                self.client.error_channel = channel
+        elif self.client.owner_id is not None:
+            self.client.error_channel = self.client.get_user(self.client.owner_id)
+
     @tasks.loop(time=SOCIALLY_ACCEPTABLE_TIME)
     @timed_task(enums.TaskType.BIRTHDAYS)
     async def check_birthdays(self, **kwargs):
         """Check if it's currently anyone's birthday"""
         _ = kwargs
 
+        # Can't happen (task isn't started if this is None), but Mypy doesn't know
+        if settings.BIRTHDAY_ANNOUNCEMENT_CHANNEL is None:
+            return
+
         now = tz_aware_now().date()
         async with self.client.postgres_session as session:
             birthdays = await get_birthdays_on_day(session, now)
 
         channel = self.client.get_channel(settings.BIRTHDAY_ANNOUNCEMENT_CHANNEL)
         if channel is None:
-            return await self.client.log_error("Unable to find channel for birthday announcements")
+            return await self.client.log_error("Unable to fetch channel for birthday announcements.")
+
+        if isinstance(channel, NON_MESSAGEABLE_CHANNEL_TYPES):
+            return await self.client.log_error(
+                f"Birthday announcement channel (id `{settings.BIRTHDAY_ANNOUNCEMENT_CHANNEL}`) is not messageable."
+            )
 
         for birthday in birthdays:
             user = self.client.get_user(birthday.user_id)
 
+            if user is None:
+                await self.client.log_error(
+                    f"Unable to fetch user with id `{birthday.user_id}` for birthday announcement"
+                )
+                continue
+
             await channel.send(random.choice(BIRTHDAY_MESSAGES).format(mention=user.mention))
 
     @check_birthdays.before_loop
@@ -143,6 +179,14 @@ class Tasks(commands.Cog):
             games = await fetch_free_games(self.client.http_session, session)
             channel = self.client.get_channel(settings.FREE_GAMES_CHANNEL)
 
+            if channel is None:
+                return await self.client.log_error("Unable to fetch channel for free games announcements.")
+
+            if isinstance(channel, NON_MESSAGEABLE_CHANNEL_TYPES):
+                return await self.client.log_error(
+                    f"Free games channel (id `{settings.FREE_GAMES_CHANNEL}`) is not messageable."
+                )
+
             for game in games:
                 await channel.send(embed=game.to_embed())
 
@@ -204,6 +248,17 @@ class Tasks(commands.Cog):
 
         async with self.client.postgres_session as db_session:
             announcements_channel = self.client.get_channel(settings.UFORA_ANNOUNCEMENTS_CHANNEL)
+
+            if announcements_channel is None:
+                return await self.client.log_error(
+                    f"Unable to fetch channel for ufora announcements (id `{settings.UFORA_ANNOUNCEMENTS_CHANNEL}`)."
+                )
+
+            if isinstance(announcements_channel, NON_MESSAGEABLE_CHANNEL_TYPES):
+                return await self.client.log_error(
+                    f"Ufora announcements channel (id `{settings.UFORA_ANNOUNCEMENTS_CHANNEL}`) is not messageable."
+                )
+
             announcements = await fetch_ufora_announcements(self.client.http_session, db_session)
 
             for announcement in announcements:
diff --git a/didier/data/embeds/error_embed.py b/didier/data/embeds/error_embed.py
index ea03bfe..696dd80 100644
--- a/didier/data/embeds/error_embed.py
+++ b/didier/data/embeds/error_embed.py
@@ -38,10 +38,10 @@ def create_error_embed(ctx: Optional[commands.Context], exception: Exception) ->
     embed = discord.Embed(title="Error", colour=discord.Colour.red())
 
     if ctx is not None:
-        if ctx.guild is None:
+        if ctx.guild is None or isinstance(ctx.channel, discord.DMChannel):
             origin = "DM"
         else:
-            origin = f"{ctx.channel.mention} ({ctx.guild.name})"
+            origin = f"<#{ctx.channel.id}> ({ctx.guild.name})"
 
         invocation = f"{ctx.author.display_name} in {origin}"
 
diff --git a/didier/data/embeds/logging_embed.py b/didier/data/embeds/logging_embed.py
index 40556f2..3a803a1 100644
--- a/didier/data/embeds/logging_embed.py
+++ b/didier/data/embeds/logging_embed.py
@@ -11,7 +11,7 @@ __all__ = ["create_logging_embed"]
 def create_logging_embed(level: int, message: str) -> discord.Embed:
     """Create an embed to send to the logging channel"""
     colours = {
-        logging.DEBUG: discord.Colour.light_gray,
+        logging.DEBUG: discord.Colour.light_grey(),
         logging.ERROR: discord.Colour.red(),
         logging.INFO: discord.Colour.blue(),
         logging.WARNING: discord.Colour.yellow(),
diff --git a/didier/data/scrapers/google.py b/didier/data/scrapers/google.py
index 389e9ae..9c10716 100644
--- a/didier/data/scrapers/google.py
+++ b/didier/data/scrapers/google.py
@@ -72,12 +72,12 @@ def get_search_results(bs: BeautifulSoup) -> list[str]:
     return list(dict.fromkeys(results))
 
 
-async def google_search(http_client: ClientSession, query: str):
+async def google_search(http_session: ClientSession, query: str):
     """Get the first 10 Google search results"""
     query = urlencode({"q": query})
 
     # Request 20 results in case of duplicates, bad matches, ...
-    async with http_client.get(f"https://www.google.com/search?{query}&num=20&hl=en") as response:
+    async with http_session.get(f"https://www.google.com/search?{query}&num=20&hl=en") as response:
         # Something went wrong
         if response.status != http.HTTPStatus.OK:
             return SearchData(query, response.status)
diff --git a/didier/didier.py b/didier/didier.py
index 97bb40c..33e6e4b 100644
--- a/didier/didier.py
+++ b/didier/didier.py
@@ -17,7 +17,7 @@ from database.utils.caches import CacheManager
 from didier.data.embeds.error_embed import create_error_embed
 from didier.data.embeds.logging_embed import create_logging_embed
 from didier.data.embeds.schedules import Schedule, parse_schedule
-from didier.exceptions import HTTPException, NoMatch
+from didier.exceptions import GetNoneException, HTTPException, NoMatch
 from didier.utils.discord.prefix import get_prefix
 from didier.utils.discord.snipe import should_snipe
 from didier.utils.easter_eggs import detect_easter_egg
@@ -33,7 +33,7 @@ class Didier(commands.Bot):
     """DIDIER <3"""
 
     database_caches: CacheManager
-    error_channel: discord.abc.Messageable
+    error_channel: Optional[discord.abc.Messageable] = None
     initial_extensions: tuple[str, ...] = ()
     http_session: ClientSession
     schedules: dict[settings.ScheduleType, Schedule] = {}
@@ -56,12 +56,17 @@ class Didier(commands.Bot):
             command_prefix=get_prefix, case_insensitive=True, intents=intents, activity=activity, status=status
         )
 
-        self.tree.on_error = self.on_app_command_error
+        # I'm not creating a custom tree, this is the way to do it
+        self.tree.on_error = self.on_app_command_error  # type: ignore[method-assign]
 
     @cached_property
     def main_guild(self) -> discord.Guild:
         """Obtain a reference to the main guild"""
-        return self.get_guild(settings.DISCORD_MAIN_GUILD)
+        guild = self.get_guild(settings.DISCORD_MAIN_GUILD)
+        if guild is None:
+            raise GetNoneException("Main guild could not be found in the bot's cache")
+
+        return guild
 
     @property
     def postgres_session(self) -> AsyncSession:
@@ -93,12 +98,6 @@ class Didier(commands.Bot):
         await self._load_initial_extensions()
         await self._load_directory_extensions("didier/cogs")
 
-        # Configure channel to send errors to
-        if settings.ERRORS_CHANNEL is not None:
-            self.error_channel = self.get_channel(settings.ERRORS_CHANNEL)
-        else:
-            self.error_channel = self.get_user(self.owner_id)
-
     def _create_ignored_directories(self):
         """Create directories that store ignored data"""
         ignored = ["files/schedules"]
@@ -152,18 +151,27 @@ class Didier(commands.Bot):
         original message instead
         """
         if ctx.message.reference is not None:
-            return await self.resolve_message(ctx.message.reference)
+            return await self.resolve_message(ctx.message.reference) or ctx.message
 
         return ctx.message
 
-    async def resolve_message(self, reference: discord.MessageReference) -> discord.Message:
+    async def resolve_message(self, reference: discord.MessageReference) -> Optional[discord.Message]:
         """Fetch a message from a reference"""
         # Message is in the cache, return it
         if reference.cached_message is not None:
             return reference.cached_message
 
+        if reference.message_id is None:
+            return None
+
         # For older messages: fetch them from the API
         channel = self.get_channel(reference.channel_id)
+        if channel is None or isinstance(
+            channel,
+            (discord.CategoryChannel, discord.ForumChannel, discord.abc.PrivateChannel),
+        ):  # Logically this can't happen, but we have to please Mypy
+            return None
+
         return await channel.fetch_message(reference.message_id)
 
     async def confirm_message(self, message: discord.Message):
@@ -184,7 +192,7 @@ class Didier(commands.Bot):
         }
 
         methods.get(level, logger.error)(message)
-        if log_to_discord:
+        if log_to_discord and self.error_channel is not None:
             embed = create_logging_embed(level, message)
             await self.error_channel.send(embed=embed)
 
@@ -253,10 +261,9 @@ class Didier(commands.Bot):
 
         await interaction.response.send_message("Something went wrong processing this command.", ephemeral=True)
 
-        if settings.ERRORS_CHANNEL is not None:
+        if self.error_channel is not None:
             embed = create_error_embed(await commands.Context.from_interaction(interaction), exception)
-            channel = self.get_channel(settings.ERRORS_CHANNEL)
-            await channel.send(embed=embed)
+            await self.error_channel.send(embed=embed)
 
     async def on_command_completion(self, ctx: commands.Context):
         """Event triggered when a message command completes successfully"""
@@ -281,7 +288,7 @@ class Didier(commands.Bot):
 
         # Hybrid command errors are wrapped in an additional error, so wrap it back out
         if isinstance(exception, commands.HybridCommandError):
-            exception = exception.original
+            exception = exception.original  # type: ignore[assignment]
 
         # Ignore exceptions that aren't important
         if isinstance(
@@ -332,10 +339,9 @@ class Didier(commands.Bot):
         # Print everything that we care about to the logs/stderr
         await super().on_command_error(ctx, exception)
 
-        if settings.ERRORS_CHANNEL is not None:
+        if self.error_channel is not None:
             embed = create_error_embed(ctx, exception)
-            channel = self.get_channel(settings.ERRORS_CHANNEL)
-            await channel.send(embed=embed)
+            await self.error_channel.send(embed=embed)
 
     async def on_message(self, message: discord.Message, /) -> None:
         """Event triggered when a message is sent"""
@@ -344,7 +350,7 @@ class Didier(commands.Bot):
             return
 
         # Boos react to people that say Dider
-        if "dider" in message.content.lower() and message.author.id != self.user.id:
+        if "dider" in message.content.lower() and self.user is not None and message.author.id != self.user.id:
             await message.add_reaction(settings.DISCORD_BOOS_REACT)
 
         # Potential custom command
@@ -389,10 +395,9 @@ class Didier(commands.Bot):
 
     async def on_task_error(self, exception: Exception):
         """Event triggered when a task raises an exception"""
-        if settings.ERRORS_CHANNEL is not None:
+        if self.error_channel:
             embed = create_error_embed(None, exception)
-            channel = self.get_channel(settings.ERRORS_CHANNEL)
-            await channel.send(embed=embed)
+            await self.error_channel.send(embed=embed)
 
     async def on_thread_create(self, thread: discord.Thread):
         """Event triggered when a new thread is created"""
diff --git a/didier/exceptions/__init__.py b/didier/exceptions/__init__.py
index 1335dd4..fa5ad13 100644
--- a/didier/exceptions/__init__.py
+++ b/didier/exceptions/__init__.py
@@ -1,6 +1,14 @@
+from .get_none_exception import GetNoneException
 from .http_exception import HTTPException
 from .missing_env import MissingEnvironmentVariable
 from .no_match import NoMatch, expect
 from .not_in_main_guild_exception import NotInMainGuildException
 
-__all__ = ["HTTPException", "MissingEnvironmentVariable", "NoMatch", "expect", "NotInMainGuildException"]
+__all__ = [
+    "GetNoneException",
+    "HTTPException",
+    "MissingEnvironmentVariable",
+    "NoMatch",
+    "expect",
+    "NotInMainGuildException",
+]
diff --git a/didier/exceptions/get_none_exception.py b/didier/exceptions/get_none_exception.py
new file mode 100644
index 0000000..cbd2f77
--- /dev/null
+++ b/didier/exceptions/get_none_exception.py
@@ -0,0 +1,5 @@
+__all__ = ["GetNoneException"]
+
+
+class GetNoneException(RuntimeError):
+    """Exception raised when a Bot.get()-method returned None"""
diff --git a/didier/exceptions/not_in_main_guild_exception.py b/didier/exceptions/not_in_main_guild_exception.py
index 5572c44..5279686 100644
--- a/didier/exceptions/not_in_main_guild_exception.py
+++ b/didier/exceptions/not_in_main_guild_exception.py
@@ -12,6 +12,6 @@ class NotInMainGuildException(ValueError):
 
     def __init__(self, user: Union[discord.User, discord.Member]):
         super().__init__(
-            f"User {user.display_name} (id {user.id}) "
-            f"is not a member of the configured main guild (id {settings.DISCORD_MAIN_GUILD})."
+            f"User {user.display_name} (id `{user.id}`) "
+            f"is not a member of the configured main guild (id `{settings.DISCORD_MAIN_GUILD}`)."
         )
diff --git a/didier/utils/discord/channels.py b/didier/utils/discord/channels.py
new file mode 100644
index 0000000..26739f8
--- /dev/null
+++ b/didier/utils/discord/channels.py
@@ -0,0 +1,5 @@
+import discord
+
+__all__ = ["NON_MESSAGEABLE_CHANNEL_TYPES"]
+
+NON_MESSAGEABLE_CHANNEL_TYPES = (discord.ForumChannel, discord.CategoryChannel, discord.abc.PrivateChannel)
diff --git a/didier/utils/discord/prefix.py b/didier/utils/discord/prefix.py
index f3fa7c4..694a4b6 100644
--- a/didier/utils/discord/prefix.py
+++ b/didier/utils/discord/prefix.py
@@ -15,11 +15,14 @@ def match_prefix(client: commands.Bot, message: Message) -> Optional[str]:
     This is done dynamically through regexes to allow case-insensitivity
     and variable amounts of whitespace among other things.
     """
-    mention = f"<@!?{client.user.id}>"
+    mention = f"<@!?{client.user.id}>" if client.user else None
     regex = r"^({})\s*"
 
     # Check which prefix was used
     for prefix in [*constants.PREFIXES, mention]:
+        if prefix is None:
+            continue
+
         match = re.match(regex.format(prefix), message.content, flags=re.I)
 
         if match is not None:
diff --git a/didier/views/modals/bookmarks.py b/didier/views/modals/bookmarks.py
index f77b608..acd4c8f 100644
--- a/didier/views/modals/bookmarks.py
+++ b/didier/views/modals/bookmarks.py
@@ -25,24 +25,24 @@ class CreateBookmark(discord.ui.Modal, title="Create Bookmark"):
 
     @overrides
     async def on_submit(self, interaction: discord.Interaction):
+        await interaction.response.defer(ephemeral=True)
+
         label = self.name.value.strip()
 
         try:
             async with self.client.postgres_session as session:
                 bm = await create_bookmark(session, interaction.user.id, label, self.jump_url)
-                return await interaction.response.send_message(
-                    f"Bookmark `{label}` successfully created (`#{bm.bookmark_id}`).", ephemeral=True
+                return await interaction.followup.send(
+                    f"Bookmark `{label}` successfully created (`#{bm.bookmark_id}`)."
                 )
         except DuplicateInsertException:
             # Label is already in use
-            return await interaction.response.send_message(
-                f"You already have a bookmark named `{label}`.", ephemeral=True
-            )
+            return await interaction.followup.send(f"You already have a bookmark named `{label}`.")
         except ForbiddenNameException:
             # Label isn't allowed
-            return await interaction.response.send_message(f"Bookmarks cannot be named `{label}`.", ephemeral=True)
+            return await interaction.followup.send(f"Bookmarks cannot be named `{label}`.")
 
     @overrides
     async def on_error(self, interaction: discord.Interaction, error: Exception):  # type: ignore
-        await interaction.response.send_message("Something went wrong.", ephemeral=True)
+        await interaction.followup.send("Something went wrong.", ephemeral=True)
         traceback.print_tb(error.__traceback__)
diff --git a/didier/views/modals/dad_jokes.py b/didier/views/modals/dad_jokes.py
index c3b2f67..5ebfab7 100644
--- a/didier/views/modals/dad_jokes.py
+++ b/didier/views/modals/dad_jokes.py
@@ -26,12 +26,14 @@ class AddDadJoke(discord.ui.Modal, title="Add Dad Joke"):
 
     @overrides
     async def on_submit(self, interaction: discord.Interaction):
+        await interaction.response.defer(ephemeral=True)
+
         async with self.client.postgres_session as session:
             joke = await add_dad_joke(session, str(self.joke.value))
 
-        await interaction.response.send_message(f"Successfully added joke #{joke.dad_joke_id}", ephemeral=True)
+        await interaction.followup.send(f"Successfully added joke #{joke.dad_joke_id}")
 
     @overrides
     async def on_error(self, interaction: discord.Interaction, error: Exception):  # type: ignore
-        await interaction.response.send_message("Something went wrong.", ephemeral=True)
+        await interaction.followup.send("Something went wrong.", ephemeral=True)
         traceback.print_tb(error.__traceback__)
diff --git a/didier/views/modals/events.py b/didier/views/modals/events.py
index e7b92b4..71acea6 100644
--- a/didier/views/modals/events.py
+++ b/didier/views/modals/events.py
@@ -10,6 +10,8 @@ from didier import Didier
 
 __all__ = ["AddEvent"]
 
+from didier.utils.discord.channels import NON_MESSAGEABLE_CHANNEL_TYPES
+
 
 class AddEvent(discord.ui.Modal, title="Add Event"):
     """Modal to add a new event"""
@@ -33,15 +35,20 @@ class AddEvent(discord.ui.Modal, title="Add Event"):
 
     @overrides
     async def on_submit(self, interaction: discord.Interaction) -> None:
+        await interaction.response.defer(ephemeral=True)
+
         try:
             parse(self.timestamp.value, dayfirst=True).replace(tzinfo=ZoneInfo("Europe/Brussels"))
         except ParserError:
-            return await interaction.response.send_message("Unable to parse date argument.", ephemeral=True)
+            return await interaction.followup.send("Unable to parse date argument.")
 
-        if self.client.get_channel(int(self.channel.value)) is None:
-            return await interaction.response.send_message(
-                f"Unable to find channel `{self.channel.value}`", ephemeral=True
-            )
+        channel = self.client.get_channel(int(self.channel.value))
+
+        if channel is None:
+            return await interaction.followup.send(f"Unable to find channel with id `{self.channel.value}`")
+
+        if isinstance(channel, NON_MESSAGEABLE_CHANNEL_TYPES):
+            return await interaction.followup.send(f"Channel with id `{self.channel.value}` is not messageable.")
 
         async with self.client.postgres_session as session:
             event = await add_event(
@@ -52,10 +59,10 @@ class AddEvent(discord.ui.Modal, title="Add Event"):
                 channel_id=int(self.channel.value),
             )
 
-        await interaction.response.send_message(f"Successfully added event `{event.event_id}`.", ephemeral=True)
+        await interaction.followup.send(f"Successfully added event `{event.event_id}`.")
         self.client.dispatch("event_create", event)
 
     @overrides
     async def on_error(self, interaction: discord.Interaction, error: Exception):  # type: ignore
-        await interaction.response.send_message("Something went wrong.", ephemeral=True)
+        await interaction.followup.send("Something went wrong.", ephemeral=True)
         traceback.print_tb(error.__traceback__)
diff --git a/settings.py b/settings.py
index 32bd5e0..a862fde 100644
--- a/settings.py
+++ b/settings.py
@@ -111,7 +111,7 @@ class ScheduleInfo:
 
     role_id: Optional[int]
     schedule_url: Optional[str]
-    name: Optional[str] = None
+    name: ScheduleType
 
 
 SCHEDULE_DATA = [