Linux appimage client and mTLS client certificates

just recently installed NextCloud on a server at home, so far I’ve got all errors sorted out and the server is working as expected.

I am using nginx as a reverse proxy to authenticate clients using mTLS before passing the client through to the server, this setup works perfect for any clients using a web browser with a client certificate installed. It also works fine from my Android device using the same client certificate and successfully synced up a couple thousand photos from my phone this afternoon.

However, when I open the appimage, punch in my server’s URL, click next, then click “Configure client-side TLS certificate”, point it at my cert.pfx file, enter the password, it throws back an error stating the password is invalid? This is the same cert.pfx and password that is installed on the browser on my laptop and works just fine, the NextCloud appimage just won’t accept it for some reason.

Is there a specific way mTLS certificates need to be generated to work with the appimage that would be causing this, or am I just doing something wrong?

What distribution, version, and version of OpenSSL?

Versions:

Nginx 1.18.0
OpenSSL 1.1.1w
NextCloud server 30.0.6
NextCloud appImage: 3.15.3-x86_64

Not sure which distribution you’re asking. The client running the app image is Mint 21.2. the server hosting Next cloud is Debian 12.9.

I should also point out when I said the cert I am using on Android works, that was with the Android app, not the android web browser