2nd screen gets no signal?

Su
- in Acer
4

My 2nd screen (connected to the laptop) gets somehow no signal. When I start it, it shows me the three connection options and is only "No Signal". My HDMI cable both the screen is not broken. I have already tested that. If I press Windows key + P and click on "Expand" nothing happens. Even in the setting, the screen is not recognized. (If anyone needs to know, the screen and my laptop are from Acer.)
Does anyone know what it could be & what can I do about it?

Da

Maybe the cable is broken or you have the wrong source indicated on the screen (probably VGA instead of HDMI?)

Su

The cable is ok. Where can you specify the source? : D

Ky

Ever pressed the Sourcetaste on the monitor?

Da

So usually the screen has some buttons / buttons somewhere with which you can usually switch directly to the sources or through which you can get into the menu and switch somewhere the sources.