After intense internet research I learned the following: You have to reset the level indicator.
This comes following dimensions (titrated from Pneuma) for devices without number field:
To reset the level indicator of the toner, please proceed as follows:
1. Switch off the power switch
2. Open the door and keep the key-press Go / Start and then on while holding down the GO / Start button power switch
3. If all the LEDs light release GO / Start button
4. After LEDs have gone 2x GO / Start button press
5. 1-2 sec. Pause
6. Press 6x GO / Start button
7. Close the flap
-> The level reset and the process is now complete
Then we went on.
I thank you for this tip and therefore wants him to pass.
MFG