Can't sign in on xbox one app

When I try to sign in it says ‘Plex pass required’.
I have linked my laptop and the xbox using the code provided for plex pass preview and it still doesn’t work. Can anyone tell me why it is not working?

As the message says the Xbox One app currently requires a Plex Pass. The client is not completed so it is only available to Plex Pass members as part of the early access program. Once the developers believe the client is ready to be released the client will either be available for a one-time fee, activated by plex-pass, or simply free. (The developers have not stated which route the app will go)