Same issue with the YouTube app on our Samsung smart TV. From the YouTube Music tab, most videos will not play. Same with the album cover and buffering icon, and same error message, with a different Playback ID of course. We also tried multiple accounts, reinstalling the app, etc.
Interestingly, the problem appears to be uniquely connected to the TV. We started a video on the YouTube phone app and it worked fine. When we casted to the TV, it tried to play for a second, then the same thing happened.
Very frustrating and haven't been able to find any solutions.