Monitor power button reset, BID (Built-in Diagnostics)

* Turn the monitor off
* Disconnect every cable (including the power cable) from the rear and side of the monitor
* If a mechanical monitor power button, press the button in for 8 seconds (clears any residual power in the circuits). If not a mechanical power button, just wait 8 seconds
* Reconnect ONLY the power cable to the monitor

* Turn the monitor on and run the BID, page 49
- If the BID does not show the issue, the monitor itself is functional. The fault lies with either the cabling, video card, video card driver, or operating system
- If the issue appears on the BID gray/red/green/blue/black/white/text screens, the monitor is defective

I have got the same exact problem and it has nothing to do with the graphic card, it is the same when I just connect the power cable and I connected two different power cables. It is not fixable, I tried what was written here. I bought this monitor in March 2019, it is an atrocity that this monitor only lasted two years and a couple of months. Funny enough, my warranty finished this year in March and then this happened. Dell no more.... Bought another monitor already from another company, because I needed one with urgency.

@VitorF_​ I feel your pain, I also have that same monitor with a build date of 2019. I has the same issue above, when connected it may also display horizontal lines and any menus are garbled.  Dell should stand behind these. Even if I had to disassembled it and replace a board, I'd be willing to do that if they provided instructions. I have thought about taking it apart to see if a connector is loose or there my be a cold solder joint but I would expect some input from Dell if those should be considered. I think a refurb exchange option would be a nice offering from Dell. Mine saw limited use and was not abused. It was used on my home desk.