Hey,
It looks like Jellyfin has closed its Reddit community permanently. I assume small subreddits will start to do this but you can see the blog post here for the announcement: The New Jellyfin Forum | Jellyfin
Looks to be a phpBB forum which makes me nostalgic. Forum can be found here:
Hope this helps anybody looking for help with Jellyfin.
Edit: it’s actually using myBB. Not phpBB
Respect the dedication. They’ve done a good job letting people know how to get in contact on all the various platforms here as well, Contact | Jellyfin.
We couldn’t quite figure out how to get Reddit Auth working for NodeBB, otherwise the community I operate probably would have done the same. It’s a quick and easy way to get users to at least sign up. Once they’re signed up you can start sending them digest messages containing top posts from the week or whatever, which will hopefully bring them back at some point. If you have to get rid of reddit auth (because of API changes or whatever) then hitting the reset password button is easy enough plenty of people would do it. It’s actually a pretty brilliant strategy.
It’s not really a big deal, but the forum is based on myBB not phpBB. We had initially tried phpBB but had issues with some plugins we considered critical not working. 
Aw, sorry about that. I made an edit to the original post.
I don’t blame them. Everyone is trying to find alternatives and what works for them. I wish them success.