Nextcloud APT Ubuntu-TLS initilization failed


I have a strange problem with the Nextcloud desktop on Ubuntu (22.04 LTS, Mate DE).

When I try to connect to my server using the desktop client downloaded with APT I always get a error TLS initialization failed.

The weird thing is that when I use flatpak, the client works perfectly, no error at all. Same thing with the appimage, it works flawlessly. All from the same computer.

My mac and my android phone were able to connect without any problem too, so I think it rules out my server as the problem…

I’d prefer to use the APT version for the integration in caja and the hability to update with everything else.

Any ideas where the problem might come from and how to solve it?