Some videos won’t play on Apple TV streamed by AirPlay

So I frequently use the option in the Media Center to stream videos I’m playing on my iPhone onto my Apple TV 4K. But often they actually won’t play on the TV, either there is a little red symbol next to the video progression bar on the TV, or it’s just loading and loading and nothing is happening, while on the phone the video seems to progress (at least the time played is moving).

Dunno why that is, hope to find a fix.

to be clear that’s mainly appearing while watching some videos online using safari and then trying to stream them onto my Apple TV.