Problem reaching Traefik inbetween FritzBox and Docker-Containers

Hello,

I think I have a problem with the configuration of my FritzBox to access the traefik container and the docker-containers behind it.

For DDNS I use MyFritz but I want to use a registered domain name. So I configured a CNAME entry fritzbox.mydomain.com with destination asdwrwerwe.myfritz.net hoping this is correct.
What exactly do I have to configure as destination concerning port-fowarding Port 80 (http) and 443 (https) in the FritzBox settings?
Traefik is already running as a docker container on my server 192.168.178.6 and using ports 80 and 443.

Thanks a lot for helping or links with information.

Kind regards
tsch