Geeetech a30 Not extruding filament

[augusvena]

Hi guys. I have a little problem with my 3d printer. When i‘m loading or unloading new fillament the printer pushes it fine through the tube. But when i start a print the filament doesn‘t move anymore. The Motor with the gear is rotating but the feeder wheel is standing still. Any suggestions? Ps the Printer is a Geeetech A30 https://showbox.tools/.