Plex and Smart TV can’t see WD PR2100any more

I had my WD PR2100 working perfectly with Plex and my smart TV. Then we had a power cut. Now the NAS drive works fine with my Mac and the WD app on my iPad. But I f I try to use the NAS with Plex on the TV I get the message that the drive is not found. It’s clearly compatible with the Smart TV and Plex because it used to work.
Any tips or advice would be really welcome! Thanks