Movies / Series Hang

I’m having this really annoying buffering issue.

What do i have:

2x Apple TV 4K Ethernet connected 1Gbit LAN

When i try to play a movie or serie from a Plex library within infuse it starts and works for like a 30-80 seconds. After this is turns into buffering mode and simply not continuing.
If i play the same media through the Plex app everything works fine.

I’m experiencing this issue since a month or two. Before it worked perfectly.

I’m clueless how to solve this issue because it works with the Plex app but not the Infuse app.
I already removed the app and reinstalled it but no luck.Everything is updated with all the latest versions.
Anyone who can point me into the direction how to solve this?