Can a container with port 80 exposed cause troubles to Traefik?

HI there,
I have a webapp in a container that is evading traefik, as nother ever shows on webapp.mydomain.com.
Somehow this container exposes port 80/tcp, regardless of the ports defined in the compose file.
Configuration is virtually identical to other containers that have no issues.

Can the exposed port be a reason that traefik is struggling with ?
What information can I offer for more details ?
Cheers