"stop watching on your other device" error playing a movie
I ran into the "stop watching on your other device" error when I tried to resume playing a movie on my AppleTV device.
The movie was rented from AppleTV/iTunes.
I had been playing the movie on an iPad. Even though I didn’t download the movie to the iPad and had quit the Apple TV app on the iPad and later even quit the iPad and restarted, I kept getting the error on my AppleTV.
The fix was to open the AppleTV app on the iPad and start playing some other movie. I then shut that down and, presto chango, the original movie was now available to play on my AppleTV device.
Apple TV 4K