SOLVED: Unable to sign in after creating a new container with the same appdata path

[TheDreadPirate]

When you say "Docker container", do you mean you use the actual docker functionality built into unRAID to run Jellyfin?

Then you say you added Jellyfin from unRAID's app tab. What I'm wondering is whether the "app" uses the same directory structure and/or the same based Jellyfin image as what you had before.

Because it sounds like you WERE using a different image than what the unRAID "app" uses. The linuxserver image for Jellyfin and the official Jellyfin image have slightly different directory structures and are not 100% interchangable. If this is what is happening then that would explain why it kind of works, but mostly not.