Web UI not loading

[psychobunny]

I'm running Jellyfin 10.9.11. We had auto-upgraded to the 10.10 series when it released but then manually downgraded and locked to 10.9.11 because we're using an SSO plugin that is not compatible with 10.10. Things were then running fine until some point in the last couple weeks when the web UI began failing to load in either a web browser or in Jellyfin Media Player.

The JS console errors I see suggest that something is going wrong pretty early on in loading the application, as document.body appears to be null (screenshot). There also appears to be an error related to not finding the reactRoot element (screenshot).

The server end of things appears to be fine—I can use Swiftfin without any issues. So it appears to be something with the web UI. Possibly related to a plugin, and I'm willing to unload some plugins, but I'm not sure how to do that if I can't load the web UI in the first place.

Thoughts on how to debug this? Thanks!

[TheDreadPirate]

You may want to consider re-evaluating your SSO provider. There has been 1 commit since June for the plugin you use.

What OS is the server running on? If installed directly on Linux, can you verify that you downgraded both the server and web packages?