Nope, I had the same experience. I don’t know how many tutorials for set up of docker and jellyfin via docker that I read/watched and tried. Eventually I found one that worked, but I am still in that steep part of the curve after having successfully set up a few containers. That said, it has worked flawlessly since install, so…

You’re adding extra layers by using an app, even the official one. You might want to try accessing through a browser. The app refused to connect for a while because of https settings.