why wont plex run on my devices

Hi All,
I have been using PLEX now for 2 years and never the slightest issue. With my setup i basically have all my media stored on my PC and I stream it to the XBOX ONE via the Plex App for Xbox.
Last week i went to watch a movie and it basically got stuck on the buffering screen? Didn’t think much of it so left for a minute and came back but still just had the black screen with the grey box and “buffering” with the turning circle.
All my play lists and content appear perfect, i just cant get anything to play. Have updated everything on the PC, deleted and reinstalled the plex app on the Xbox and I’m still getting nothing but a buffering screen.
Any help would be GREATLY appreciated!
Thank you