Linux Desktop Client 5.2.1 on Ubuntu & TLS: Problem with new Let'sEncrypt Cert:-(

My ownCloud installation worked fine for many years. It even moved from my bookshelf to an AWS hosted server two years ago. All that time, the desktop client was fine with the regularly rotated Let’sEncrypt certs.
The problem: my cert was renewed last night. The ssllabs server test is fine & Firefox & Chrome (on the same fully patched Ubuntu 22.04) are happy to connect to the server. But the ownCloud client reports:

I triedto find the reported fingerprints but I don’t see them in the cert chain in Firefox or Chrome:-( I don’t see any settings to influence the root CA’s, the ownCloud client would use?! So, I assume, it’s using the system roots?

Any idea?

– Marco

I have the same problem.
The thing is, it shows me the same Fingerprint like you. So this is strange.
I also try to reinstall the packages, but I get still this certification warning.

On Linux?

take a backup of $HOME/.config/ownCloud/owncloud.cfg and look if there is a line starting with ‘0\General\CaCertificates=’ and remove that. That helped me;-)

– Marco