SOLVED: All client connections are black screen

[Nathanael]

I did what you said and it made no change to the connection.

The backend of Jellyfin seems to be working fine. Both from LAN and not. I connected VIA Kodi and that worked fine, my issue seems to be with the Web client and so it affects the desktop and mobile clients as well. Anything that connects without the web client is unaffected. So my next thought would be reinstalling the web client, but how would I go about that without deleting everything?