Nintendo Switch pro controller no longer connects?

My pro controller connected without any problems a few hours ago, but it no longer connects to my switch when my friend's switch connects, but can someone help me?

Controllers are only registered on one console, you have to press the sync button on the back of the controller on the Pro controller when you change the order of the controller in the home menu. Or alternatively, I think you can connect it to the dock with a cable. But if he is now registered with your friend, then you should have done something like that with him before, right?

Go into the system settings. Then in the menu "Controllers and Sensors". Then click on "Unsynchronize Controllers".

Then try again to connect the controller via "Change fingering / order".

Was the only thing that helped with me.