An unexpected playback problem occurred

I’m curious if your issue is the same as what some others are experiencing. Trying to see how far back this issue goes. Looks like you’re running a windows server. Are you doing hardware transcoding? If so, try disabling hardware acceleration setting in the PMS > Transcode settings area and see if the issue persists. It could be that your other TVs are direct playing and this other TV not working is transcoding media, which would be why some devices are working and another one isn’t. Though you saying it won’t let them playback anything is a bit odd as the issue I’m seeing is related to VC1 media only so far in my tests. VC1 can be seen in the media “Get Info” option in the little … drop down menu, which should bring up this window and show you the codec the media was encoded with:

If your issue turns out to be transcoding, please join my forum post and let us know: