I have been using Plex on WD MyCloudEX2Ultra to play mp4 files I created. As of yesterday (5/27/21) I can’t play these files on Fire TV, nor from my fire tablet. I get message “server not powerful enough to convert video”. I am still able to play the videos from ios devices.
What version of PMS is currently active on your WD MyCloud Home?
There’s been a number of reports from WD users who are stuck on a 12+ months old PMS version with newer Plex client apps on Android (TV).