HDMI / Displayport adapter not working?

I would like to connect my Linux laptop to our television. I bought a display port to HDMI adapter. Now I have connected it but only "no signal" is displayed on the TV. I can't explain why that is.

I already have:

- Both devices restarted

- Checked the receipt

- The HDMI cable is functional

I'm currently With my grandparents and at home I have often used such a connection.

Anyone have an idea?

Lg. And thanks in advance

Do you have to activate the output in the OS somehow? In Windows you control the type of output on secondary screens with WIN + P. Could it be that you have to adjust somewhere in the settings how the second display is managed?

I've already browsed through the settings in my laptop… Somehow I didn't find any of the same.

The key combination (Fn & F7) that my father (he has the same laptop) uses to call up the settings for a second screen does not work for me either. (No window opens. Just keep everything as it was…)