A few days ago it seems, all channels give a connection lost error after a minute or two of watching. Last weekend there was also problems that the same happened after watching a bit longer.
Same AppleTV and HDHomerun with HDHomerun app has no problems watching live TV.
We need more details. How are the Apple TV and your DVR server connected to the network? What hardware are you running the server on? Do you have tuner sharing enabled on the client? Does it only happen when watching live or also when watching recordings?
Wired network, no DVR server (because of EPG data issues here in Finland). Where do I find out whether tuner sharing is on or off?
Further info. Our other AppleTV (non-HD version) works correctly. Only this main one has this issue. Connection drops so ofter, watching is impossible.
And now another reboot seems to have corrected the issue for now...
If you don’t have a DVR server this option doesn’t exist. Glad to hear the reboot fixed it for you.
Well, actually it seems that the problem is not totally gone after all. Now it takes a while (30+min) before the same error pops up. Happened a few times tonight.
Since there is no DVR server the conversation only involves your Apple TV and your HDHomeRun tuner. So the issue has to be in that connection somewhere. Are they both connected to the same network switch? You could also look at the web interface of the HDHomeRun and look at the logs and see what they say at the time of the issue.
Both devices are connected to the same HP gigabit switch.
HDHomerun logs only shows this at the time of error:
20211030-18:02:13 Tuner: tuner0 tuning 4 Nelonen HD (a8qam256-6900:290MHz-444)
20211030-18:02:13 Tuner: tuner0 streaming http to XXX.XXX.XXX.XXX:49349
20211030-18:02:15 Tuner: tuner0 lockkey forced release by 10.0.1.2
20211030-18:56:00 Tuner: tuner0 http stream ended (stop request)
20211030-18:56:18 Tuner: tuner0 tuning 4 Nelonen HD (a8qam256-6900:290MHz-444)
20211030-18:56:18 Tuner: tuner0 streaming http to 10.0.1.2:49352
20211030-18:56:20 Tuner: tuner0 lockkey forced release by 10.0.1.2
20211030-19:35:26 Tuner: tuner0 http stream ended (stop request)
Also, HDHomerun app does not have these issues on the same AppleTV. Sure this is a network issue?
Submit diagnostics after it happens
Just happened a minute ago, sent diagnostics logs.
This time I only watched for about 30 secs.
Here is the log from HDHomerun:
20211101-16:54:11 Tuner: tuner0 tuning 1 YLE TV1 HD (a8qam256-6900:290MHz-1501)
20211101-16:54:11 Tuner: tuner0 streaming http to 10.0.1.2:49260
20211101-16:54:13 Tuner: tuner0 lockkey forced release by 10.0.1.2
20211101-16:54:52 Tuner: tuner0 http stream ended (stop request)
20211101-16:54:56 Tuner: tuner0 tuning 1 YLE TV1 HD (a8qam256-6900:290MHz-1501)
20211101-16:54:56 Tuner: tuner0 streaming http to 10.0.1.2:49263
20211101-16:54:58 Tuner: tuner0 lockkey forced release by 10.0.1.2
20211101-16:55:21 Tuner: tuner0 http stream ended (stop request)
I reselected the channel right after the connection lost appeared.
Ok, now it seems I can only watch under a minute before connection lost happens every time I tune into a channel. 
So it turns out Channels is totally unusable for this reason now Any updates on this issue?
Which version app are you using? Can you update to 5.1.0 from the app store and try that one?
Already using 5.0.1.
For some reason now it only works for about 5 seconds before connection lost... HDHomerun app has no problems on the same AppleTV.
Your Apple TV is out of disk space. You need to delete some apps or clear caches to free up space
Thanks, I was sure you can figure this out! 