@phaedrux
In fact that was the problem. It is working now.
I learned something new!! Thank you

In addition to my former reply, in the homez.g you will see a G92 Z2.1 that is one experience I made. Is not there anymore!

@Phaedrux
Thank You

@kareka
First of all thank you!
The files are:
config.g
config-override.g

I upgraded my RRF to 3.4.2. Adjusted the config.g accordingly as follows:

Previously i had RRF 3.2.2 ver stable and working fine. Now the situation is that no matter what I put in the z parameter (G31 P25 X27 Y0 Z3.1) the result is always the same. This means that I am not able to adjust the z-offset. I already searched for this without success. Can someone give me an insight.

I ugraded my DUET2wifi firmware for v3.2.2 and the cura slicing is not start the cooling fan. It generates M106 S255 (for 100% speed) and this version requires M106 P0 S255. It is necessary to specify the configure port. Is there any way to configure CURA for this? Help is most welcome!