Lately, I’ve noticed that when sending a video to Channels on Apple TV from a Channels iOS client, sometimes results in a black screen and the video never plays. If I send the exact same video again, it always works the 2nd time. Any thoughts?
I am not sure what you mean here. Channels does not support AirPlay.
Do you mean the "Play to" functionality, where you can request the server initiate playback on different devices? Or do you mean something else?
If the former, if you request playback on your iOS device, do you also experience inability to play the first time? If so, the issue may be with your storage device being asleep, and unable to spin up quickly enough.
Yes, I was referring to the latter not AirPlay. That said, I don’t experience this issue on my iOS devices and my external hard drive is set to never sleep. I’ve used this feature extensively and just recently I’ve noticed this issue intermittently occurring….
Since this is a new development, that would imply something has changed. Are there any networking changes that occurred? Any hardware changes? Major software updates?
Huh? I just finished watching a show using Channels on my iPhone and displaying it via AirPlay to a Roku connected to my TV.
No changes on my end either hardware of software outside of the,Channels beta updates both for Apple TV and iOS.
You may be thinking of screen mirroring. But Channels has never supported AirPlay. (Their custom video player precludes supporting it.)
This is not related to AirPlay. This is regarding the play to feature from Channels via iOS/iPadOS.
No wifi mesh networks or anything of that sort? Absolutely nothing has changed or happened from when it worked flawlessly to when it didn't?
And if absolutely nothing in your end changed, can you recall which versions introduced the change? And since you stated you're running beta-pre-release versions, have you tried rolling back to previous versions to see if that addresses the issues?
(Including details is always helpful. Software versions, OS versions, etc. ... Also, you're running beta versions; does this also occur with the stable/release versions—Apple allows both to exist together on the system?)
Unfortunately I can’t pinpoint this to a specific version, date, etc. I really just wanted to report it in the hopes that possibly others have experienced this and it could be investigated. I’ll continue to test and see if I can find a reproducible pattern…
Hi please submit diagnostics from the client next time it happens and we'll take a look.
Ah, yes I was using screen mirroring...but the net effect is the same: the TV plays the video/audio, and my phone has ff/rew/pause/play controls and a TV icon in the middle of its screen
I just tested over here and can corroborate your report, I am experiencing the same — the first “cast to TV” command fails and the second attempt succeeds. It was not like like before.
I submitted diagnostics and hope this helps.
EDIT TO ADD: it seems to be working properly now for me so this issue is not consistent 
Could someone post a video of what they’re seeing?
Is the video player trying to start and it’s black, and you have to back out of it?
Or is just nothing happening at all.
Go figure, it’s working properly for me now. If it happens again, I will grab video. I did manage to send diagnostics though.
What I experienced was the same as Ahwman described in the OP. With the first attempt, the TV display goes black, as if the video is about to play, but it doesn’t actually play. On the phone, I then tap the watch button a 2nd time, choose AppleTV, and then it plays immediately. This happened for me at least 3 times in a row. Now it’s working fine.
By the way, navigating a Channels DVR this way has always been an absolute joy. Who needs PIP? 
Exactly what I’m experiencing. Thank you for corroborating and hopefully the devs can get to the bottom of this as I absolutely love this feature, especially in iOS shortcuts…
Just submitted diagnostics, hope it helps 
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This issue occurred yet again today and I was able to time stamp it at 12:01 PM EST on 02/24/24. I also resubmitted diagnostics. Hope this is helpful…
My experience thus far is that it happens after an extended period of inactivity. After a few attempts, it then it starts working fine, at least for a bit. Only for it to return in a few hours, like the next morning.
After more testing, I can duplicate this issue 100% of the time. In my case, it only occurs if I am currently tuned into a live TVE channel and then attempt to play content from Channels on my iPad or iPhone to the same Apple TV.