Video Unavailable on AppleTV App on Samsung TV 2019

Recently, I bought two movies from Apple's TV app. When playing it on my Samsung TV, that has the AppleTV app integrated, the movies suddenly stop and the message

"Video Unavailable - This video isn't availalbe to watch. Wait a moment, then try again."

After trying again by exiting the movie and start it again from where I was cut out, the message came on again another two or three times and I had to repeat the process. Finally, I was able to continue watching the movie to its end.

Why is it, that movies I buy can't be played without interruption? Why do I get this message in the middle of watching the movies?