Nozzle distance flatbed

Hi. I own already more then 2 years the Ender 5 plus. Firmware 1.70.1 BL. And printed already some objects.
All of a sudden between 2 printjobs the distance between the nozzle and the hotbed remains approxm. 1cm. I adjusted the distance with the 4 black knobbs until a sheet of paper fits between nozzle and bed. I start printing and distance is again 1cm, so print failes. Again I follow the steps at page 10 of the manual, Aux leveling. But as said, when starting a new printjob the distance is again 1cm approxm. The selected printjob is executed before with success. Anybody any idea?
Grz Ronald

Hello @Ronaldjm ,

Did you ever figure this problem out…?