I have Live TV/DVR setup with an HDHomeRun Connect. The guide works fine on every client, and looks awesome. When I attempt to watch a show, it works every time for me on the web client, but maybe 1 time out of 3 on the AppleTV client running on an AppleTV 4k, and about the same on the iOS client. When it doesn’t work, I don’t get an error, I just get the spinning wheel on a black screen as the video never starts. I’ve waited quite a while for an error to pop up, and I’ve never seen one.
If the video manages to start on the AppleTV or iOS, it’s solid and stable.
The clients that don’t work are on the same LAN as the web client that does work and the server.
I also have this problem and found that if the screen is dark and you see the spinning wheel you can tap the apple remote as if you were going to fast forward or rewind. If you scrub to the present time in the timeline (current time) it will start playing.
It appears the player in iOS and Apple TV doesn’t automatically set the player position to the current time. It looks like the GUI is showing exactly 50% in the show timeline regardless if the show just started or is about to end.