Note: I'm using an Apple TV 4k connected to a 65" LG OLEDC7 series TV.
I too am having this problem and it just started today. It was working fine last night, as it has every day since we purchased the Apple TV 4k a few months ago, but now it's having problems. More specifically, this evening when we turned on our Apple TV, it worked fine. Then, we went to the HBO Go App to watch Game of Thrones. Everything was still fine and we could see the HBO Go Menu, select a series, and play it. Unfortunately, after starting the episode, the TV went black. We could hear the audio, but not see a picture. As a result, we backed out and restarted the app. That didn't fix anything and we still had the same problem. So we tried a different HBO Series other than GoT within the HBO Go app. Same problem. So then we restarted the Apple TV 4k itself. Still the same problem. So then we tried a different app--Amazon Prime. Same problem. Then we tried the Netflix app and still the same problem. After doing this several times, and why the screen was still black, the following message popped up on my TV screen, "This video can't be played. It looks like your HDMI cable or connection doesn't support HDCP, which is required to play this type of video. Try reconnecting the HDMI cable from the Apple TV to your TV, and play this video again." So we did that, but still the same problem.
So then I went to settings and verified the Apple TV 4k is up to date. I also "checked the cable" and it verified that my HDMI Cable and TV are capable of running Dolby Vision 4k at 60hz--the very best resolution Apple TV 4k can put out. Tried watching an episode of GoT and still the same problem--a black screen while the audio plays.
Although this HDMI cable is new and the Apple TV 4k verified it is working properly (see above), I nevertheless tried using different cables and hooding them to different TV inputs. Still the same problem. I just don't understand.
This is all so odd and disappointing. I'm a huge Apple fan and based on all the comments in this thread and related blogs, there is clearly an issue with the Apple TV 4k itself. I also find it odd that mine started happening problems today after it worked completely fine last night. Was there a recent update early this morning or late last night?
I hope somebody can release a patch to fix this glitch.
