I had a similar issue 3 days ago. It happened out of the blue. I discovered I could not play a single video from any of my streaming apps. But if I restarted the device, it worked perfectly again.
It took me about a day of hourly restarts to realise the precursor or trigger for this event. The precursor was my Apple TV 4K going into screen saver mode (on my device, this normally happens after 1-2 mins of inactivity); if I tried to play a TV or movie afterwards, nothing would happen. I simply couldn’t play any videos. I soon also discovered, that I also couldn’t AirPlay videos to my Apple TV 4K - If I tried streaming a purchased movie from my Apple TV app on my iPad to my Apple TV (something I’ve done hundreds of time before) my iPad generated a notification saying something like this “the file format for this movie is incompatible on the destination device”. Of course, such a notification is obviously incredulous and ridiculous as I’ve successfully played this exact movie on my Apple TV many many times and it’s in the native MP4 format supported by all Apple devices. In other words, this was another example of the bug/problem effecting my Apple TV.
My initial workaround was resetting the device whenever the fault appeared - as this restored function. Annoying but it was an effective workaround at least. But after resetting it 9x yesterday I decided it was time to call Apple Support.
SOLUTION: I’ve just spoken with the very ever so helpful Apple Support. They were brilliant. They talked me through the situation. Basically what worked to resolve this was a very simple solution indeed - go to settings/ system and press restart + the very moment after you’ve pressed restart - pull out the power cord 🔌 at back of Apple TV - and wait 1 minute before reconnecting.
I’m really not sure why the standard restart sequence that I tried 15x never worked but this hard restart did. The fact is, it just did. I’ll report back if the issue returns but it’s been 24 hrs thus far and it’s working perfectly so fingers crossed 🤞
