Hello,
I had already successfully set up the Teddycloud with my FRITZ! Box. However, the connection suddenly stopped working after I tested Pi-Hole or Adguard Home.
Here is the solution for Pi-Hole:
In Pi-hole under Settings > DNS activate the Conditional Forwarding
The solution for Adguard Home:
Under Settings > DNS Settings, enter the following as the first entry under Upstream DNS Server:
[/Fritz.box/]192.168.178.1
Now you can test whether it works again if you briefly disconnect the network connection and then call up http://tc.fritz.box.
The URL should now work again and the Toniebix should be online again in the Teddycloud.