FVP-5000T no longer able to stream media

So here we are 3 months in to the ownership of this box and now it refuses to stream movies from my Mac, previously it was doing this without issue.
Box is connected to Mac via ethernet cable, box sees the Mac and can navigate to the folder containing the movies but when I select a movie all I get is a black screen with
the Play and Advance and Stop buttons. It also refuse to play music but curiously will show images. The software is up to date. The box has been powered down and then
back up with no improvement. Any ideas or similar experiences.