Cetus2 prints approx. 5 cm above the print bed

My Cetus2 is only printing in the air. I’ve tried several STL files in Up Studio 3 and Cura, but despite auto-leveling, it starts printing about 5 cm above the plate.
Since I’m a total beginner, please explain in simple terms what I can do.
Und am liebsten in deutsch.

I was just working on my Cetus2 and finally got it printing.

Are you using the original mainboard and firmware, or Klipper and Wand?