After Update no access from the internet

I am new here. So hello to everybody.
I installed an Univention Corporate Server (UCS) and nextcloud from the App-Center.
Everything worked fine:

  • access from the local network: OK
  • access from the internet via portforwarding and dyndns: OK

Then I updated the UCS and the nextcloud on the UCS to the latest version. Since then I cannot access nextcloud from the internet any longer: “” fails on Windows, Android and iOS, via nextcloud-app and via Browser.
I added “domain.dyndns,org” and “” to the “trusted Domains” section in the /var/lib/univention-appcenter/apps/nextcloud/conf/config/config.php.
Still the same error.
Still the same error.
My searches in this forum and in searchengines where without success.

Nextcloud Version: 13.0.4-0
UCS Version: 4.3-1 errata 151

I hope for some help / advise.
Best regards

to be added:

When I try to access nextcloud via webbrowser (firefox) on “” I get an error “Zugriff über eine nicht vertrauenswürdige Domain”. The Button with the link https://vlixucs01.domain.internal/
does not work because the address ist wrong. It is the internal server-address.

So the webserver works but nextcloud will not set my dyndns-adress to trusted domains.

I have solved similar issues by opening the non working link while being in the local network. So first from external in browser go to the link to add to trusted domains, then connect to local network and do the actual adding from there. Probably you need to modify the link to reflect the server ip if needed

Nice greets Gerd