Apple Remote and Mac mini wont pair

My remote works fine with Mac mini and Plex and Sofa Control. But I am unable to pair them. The settings are right and when I press Menu + Fwd nothing happens, no Pairing icon on the screen.

The situation is a frustration since I have an Apple TV besides connected to a second Apple Remote. Since my Mac mini wont pair, the Apple TV remote controls them both.

Does anyone had a similar problem and found a sollution?