Out of filament with a full role of material… changed the role, after a few minutes again the message that the printer was out of filament…
Opened the Filament run-out sensor and saw what the problem was. The little spring was no longer on its position, and therefor the sensor optical part was “unblocked” what means out of filament.
Put the little spring back, closed the sensor and put it back in the printer… Everything is working OK again…
Spring is located between the little lever with brass colored wheel and the housing… on the photo it is back on position!