Xbox One removed from authorized device from account

Hi,

I wanted to switch the account I was using on my Xbox One’s Plex app so I went on my old account and removed my Xbox One app from the authorized devices list.
Since I did, I can’t load the Plex app anymore : it says “Plex is not reachable”. I have reinstall the app many times, reset my Xbox (while keeping the games & apps) and I am still stuck with this…

Is there any solution for me ? Now I can’t use Plex anymore on my TV this is so regrettable…

Thanks for your help

Hum, I tried to delete my old account and I am still stuck on this “Plex is not reachable” screen …
What should I do ?? …

You should be able to sign out/sign in of the app via the top right user menu, do you not see that?