Xbox one tv not getting signal from comcast box

I have the X1 Comcast DVR box too. Trying to set it up with XBOX ONE. The HDMI Out from the comcast box is going into the HDMI IN for XBOX ONE. I see no signal. Comcast confirms me that they are able to ping the box and signal is fine. Am I missing a setting
that I have to do in XBOX ONE to make it working? Asking for help?

Getting the "We've lost your TV signal" message along with video hangs with some throughput on new Xbox One. Using the Comcast Explorer 8300HD with HDMI pass-thru.

Throughput to cable box is excellent (5) and absolutely no issues when not hooked up to Xbox One.

Appears this is a Comcast/Xbox One problem?

I've had my Xbox One loose the signal so I had to unplug my cable box from the Xbox and back into the TV. It worked fine. I heard that the TV app has some issues and some times looses connection. But I also have not be able to get my X1 box to work with
my Xbox One. I used both Comcast and Xfinity but nothing.

I just tried something similar. Because the XBOX Ones TV interface is not as good as the Comcast Cable Box's I wanted to buy a splitter and run the cable box to the splitter and then split the signal - one directly to the TV HDMI 1 and another to the XBOX
one and then into the TVs HDMI 2. I wanted to be able to use the XBOX One TV while playing XBOX and then just use my Cable Box when not using the XBOX. It did not work. I received an error message that stated my cable signal was being compromised. I also could
not get a TV signal to my XBOX One. I was told that I may need a splitter with a switch. I was hoping to avoid that. I didnt want to have to switch each time but if I have to I will.....Anyone out there have any suggestions or similar experiences?

I just started having this same issue. It had been working properly for one year. But suddenly the TV signal from my Comcast cable box began to cut in and out, and eventually just displays a blue screen (though someitmes it flashes to "Your TV signal
was lost" then flashes back to blue).

At first I thought it was my cable box, so I replaced that. Then I replaced the HDMI cable.

Everything else on the XBOX works fine. And if I connect my cable box direct to my TV, it works fine. So it must be with the XBOX One itself.

...and my warranty expired. Great.