Hi ilansa, I would suggest you return it to the store for replacement/repair.
I've heard of firmware updates that cause this, but not a clear-cut solution, unfortunately.
When I had that problem, Sony just advised to do a hard reset through safe mode (which did not work).
Just make sure everything else is working on your side, like connecting another device to the HDMI port, or connecting the PS4 to another HDMI port you know is working, etc. before you return it.