I have done several Cold Pulls, with several calibration durations. Nothing changed. Also the first Layer Calibration didn't worked.
I disassemble the nozzle again and had a closer look at the nozzle. I do not how i have done this, but i damaged the front of the Extruder
I pretty sure that this is the reason why the failure accures. For now i have to wait until my new nozzle arrives.
Thanks for the help!