Tried adding proper IPv6 support

roles/docker/files/daemon.json

@@ -2,5 +2,7 @@
     "metrics-addr" : "0.0.0.0:9323",
     "experimental" : true,
     "mtu": 1450,
-    "network-control-plane-mtu": 1450
+    "network-control-plane-mtu": 1450,
+    "ipv6": true,
+    "fixed-cidr-v6": "fd00::/80"
 }

roles/networking/tasks/main.yml

@@ -34,6 +34,15 @@
     - 4789  # overlay network traffic
     - 9001  # Portainer communication
 
+# - name: Open up ports for proper IPv6 service communication
+#   community.general.ufw:
+#     rule: allow
+#     port: "{{ item }}"
+#   loop:
+#     - 80  # HTTP
+#     - 443  # HTTPS
+#     - 8000 # Portainer edge communication
+
 - name: Block everything else by default & enable firewall.
   community.general.ufw:
     default: deny