Linux desktop app not connecting to self-hosted server with self-signed certificate

I have an issue with the Linux desktop client (appImage) not connecting to my self-hosted server.
The server is using a self-signed certificate.
The certificate works with iPhone and browser. I did import the crt file into my local LinuxMint OS.
Yet, the Linux client does not connect. I am assuming it is due to a certificate issue, because I initially had that same issue on the iPhone and browser clients too (until I installed the cert), but the error message is non-descriptive.
I am wondering if the problem is that the appImage way of doing things does not allow the client to pick up the certificate I installed on my machine?
What else could it be, or where can I get a more descriptive client error message for debugging?

Thank you in advance

How did you generate this cert? Yourself or through the installer?

I created it myself

It’s likely missing some params for trust with chromium then. See