Suddenly the controller stopped working (no tracking). Also, re-pairing not possible.

[Tobias Claren]

Hello.

 

Yesterday, the controller virtually (not really) fell to the virtual ground during use.
Then he did not work anymore.
There was no impact before, I had it in my hand.
I switched it off and on, but it was gone.
I tried to reconnect it, but he says I have to disable one of the two registered controllers first.
I turn off the controller and the pairing window appears. I start the pairing process (system and menu button).
Then it flashes slowly (!) Blue, but the controller is not paired.
With the other controller, it quickly flashes blue, and it is paired immediately.

What can I do. Do I have to buy a new controller? Or is the defect a known problem?