Why does my screen go black after switching from 60Hz to 120Hz

For starters this is a brand that I've never heard of and is almost certainly some kind of low end re-badge. There is no display at this price, that will display 120 Hz signal, they've obviously overclocked and hacked the firmware,

They don't provide any sort of internal specifications be on their claim of 165 Hz, and their answer to "what is refresh rate" describes a CRT monitor and not an LCD.

let me put it this way, the electronics required to drive 120 Hz likely cost more than the retail price of this unit. I would return it if you can and buy a much better, much more expensive monitor. What you're looking for starts around $300

I would return this as quickly as possible

Hello Ollie, this is Manuela. I'm an Independent Advisor and community user like you, ready to assist with this.
Not a Microsoft employee.

What monitor is the one you have?
Additionally, may I know if you tried to lower the resolution and then set 120Hz to see if that helps?

Its like 60hz works but when i put on 120hz it goes black screen

I'm not really sure where some of the information in this Thread comes from? But a 120Hz HDTV does not try to Interlace a 1080p Source at 60hz. It simply runs the Source Content at 60Hz. I have a 120Hz Smart HDTV and it simply
goes to 1080p at 60Hz when my Xbox is turned on.

It worked on the same screens and it didn't on the same.

At least I can play.

Could you also tell me why I get a black screen when I switch to 120hz while my monitor supports 144hz