I just got my screen yesterday. With one cable, it works fine. I connected both cable and turn the 4K-144Hz mode one and then it become black. If I turn it off, the screen doesnt come back either. I need to do a hard reset of the computer and remove one of the cable in order to get an image back.
The first time I tried, it worked though. Then I switch on HDR because I wanted to see if it works and it turned back. And since then, I cannot get any image out with the 4K-144Hz.
Could it be that Windows is locked in HDR mode with the double cable mode? I cant see anything so I cant know what it is going on and cant switch it off, assuming it was on in the first place
Help is very much appreciated