Hi,
in this case, the host’s /etc/hosts file seamed to cause the issue.
It had an entry like this:
127.0.0.1 localhost crm.ecomsilio.de
So the docker containers assoziated the the domain name crm.ecomsilio.de always with the ip address 127.0.0.1. I guess this could be prevented by modifying the hosts file within the containers to overwrite this behavior. Currently, I’m not sure about the priority of each individual hosts file.