New WD My Book 3T USB3 drive giving errors

I have written my video files onto a new WD My Book 3T USB3 drive. Now, my WD Live TV media player says it doesn’t like the format of my MP4 files (although these same files work fine using an older, smaller drive), although the the media player does recognize the TS files. Any suggestions?

Post in the TV section you’ll get help faster.

Joe