Integration URLs not accessible from nextcloud container

Hello all,

Im on the latest nextcloud install on podman I did an update and can no longer use collabora office. Nextcloud and other stuff is located in a DMZ- zone. In front of nextcloud and collabora is ha-proxy doing the ssl termination. Collabora is running and Im getting an ok accessing it via browser over lan. But I dont get it from administering the office URL in nextcloud. I checked DNS in container and all is okay.
Im having same issue with intregrating xwiki and open-project. xwiki.doamin.tld, office.domain.tld…
It seems something has changed. How I get the integration running?

Can someone help?
Tia
Stefan