I’m having trouble with imported movies. So far in my testing, all imported movies play perfect on my iPhone. When trying to view certain movies on my Apple TV 4K, certain movies will open then immediately close. I attached screen shots of two examples: Harry Potter (Goblet of Fire) - which won’t play on the Apple TV 4K but will play on my iPhone.
Harry Potter (Deathly Hallows 2) - which plays just fine on all devices including the Apple TV 4K.