I'm using a custom channel with the M3U bellow in Channels DVR. This feed, when streamed via (safari, VLC or any other m3u capable streaming client) on MacOs of IOS works fine. However, when I stream it via channels Apple TV App , IOS app or browser, it freeze and buffer than freeze again every 5-10 seconds. I am using Channels DVR 2022.03.23.0209 using Docker un Unraid 6.9.2 . All the tests were done using Apple TV4K using ethernet on TVOS 15.4.1 and IOS and IPADOS 15.4.1. I have generated the following support log ac92d39b-14a1-475f-bc8d-e23ad274d8bf.
Everything in the DVR logs looks fine. The m3u8 link you specified just returns Access Denied, so I can't really dig into that part further.
Can you re-create this issue and then once you have, submit diagnostics from the tvOS app?
Please go to Settings -> Support -> Submit Diagnostic Logs from your device and let us know when it's been submitted so we can have a better idea of what was going on.