2nd monitor does not get a signal?

I have connected my monitor to my laptop, but there's no input signal on the monitor itself.

The monitor is recognized by the computer and is also recognized under the NVIDIA system settings. The HDMI cable works too, because I use it for the Playstation and it works there. Unfortunately I can't find the mistake…

Wrong input set on the monitor?

Have tried all inputs

You can toggle the settings. Ie to switch from laptop to external and both.