Parallels 14, Sierra and Itunes movies: Wont Play

I think I'm getting the exact same thing - It looks like it is specifically a problem with iTunes DRM video. I confirmed I could play my own videos in the same format and they worked via Quicktime. One "Theory" (and look, it might not be valid) is that it could be related to iTunes thinking your video is on an "invalid" display (a projector, rather than an internal monitor). Like I said it's a theory... ‍♂️