So my wife and I are running into (what I hope) is a bug.
I launch the app with my Xbox account signed in and it asks me register with the pin on plex.tv/pin. I do that and everything works great.
When my wife launches the app with her Xbox account it asks her to register with the pin, that makes sense since it's a different xbox account, so I go and register it and the app works great.
The problem is when I then try to use my Xbox account again I get prompted to register again. If I do, the next time my wife tries to use it she'll get prompted. Rinse and repeat.
Please don't tell me only one user on a given Xbox can use the app. That just won't work in a multi person house.
Trying to use one plex account (the one with a lifetime plex pass). I am only trying to use a single device, a single xbox one, but depending on who's home at a given time different users will be logged in.