Video Not Playing for Only Select Members

I use watch2gether with one other person, and up until a few days ago, it was working perfectly for us. But now, whenever one of us chooses a video to play, it plays for them but I get stuck with a black screen instead of the video. Any help for fixing this would be appreciated.

This could be caused by some browser extension. “Popper Blocker” for example, see: Issues with Popper Blocker Browser Extension

Please try to disable any installed extensions one by one and see if that makes a difference.