Check your cable, is it too long? Try switching it out first just to make sure its not a problem with the cable itself. This has happened many times to me, so its always one of the first things I check:
Also (WINDOWS KEY + P) command, will bring your project menu. And try selecting "duplicate" and see if that pops it on.
Also: once you have determined that it is not a problem with the cable, and the above WINDOWS+P command doesn't work, go to your desktop>right click anywhere on desktop>display settings> how many monitors are listed there after you click "identify" then "detect"?
After trying the above....if it still nothing....Id disconnect the monitor's hdmi/display cable, update your GPU drivers, then reconnect the HDMI/display cable.
That's a nice GPU!
Another thing to check: check the monitor's native resolution, if your display resolution in windows to is set to 4k.....but your monitor only does 1080p or 1440p....then it wont come on because the display is out of range (of resolution)
Just a few suggestions there, perfect starting point(s) to begin to troubleshoot the issue. If none of these suggestions lead you to the answer (or begin t), then we'll go further
Sincerely,
Z
ADD EDIT:
Above didn't work? Sure the cable is good by trying it on a different device? Try it in a different port on your GPU to see if the issue occurs on other ports as well.