Plex for Xbox one suddenly stopped working

I have had my Plex server running on my iMac for months now and suddenly the app on my Xbox can not access it. I’e tried reinstalling both on my Xbox and iMac but nothing has worked so far. Even op the web player inside the Plex App for mac files will no longer play.

On the xbox it shows as

Error
Server not available

There was an error communicating with the server iMac. You can Retry or Go Home to select a different one.

on the iMac it just keeps loading for ever.