Hello and thank you.
After searching the forum I could find some hint that helped me out of it.
I removed the files in this directory:
\\X-Plane 11\Output\preferences
Better, I made a back up and deleted then all files inside of it.
I lost all assignments but later on I copied the old file back and it worked.
Hope this helps other users too, after update to new releases.
Regards, Thilo