Hi Gunny and all,
Thank you so much for your help.
I think we know now what went wrong. Somehow, the ascom driver switched by itselfe from Pers driver to the 10Micron Mount driver. Doing so, the -5min were automatically changed to 0 and pier flip did not work.
We deinstalled the 10Micron mount driver and tonight pier flip did work. We are very happy!
unfortunately, the plate solver moved the object to the wrong position. We did try that as a dry run (as we always do) and it worker about 3 times in a row very well. But, as usual, not at the real test. At the moment, we are unsure why that did not work after the Flip.
Maybe someone has that problem too? (We use astronomy.net local server)
Best regards,
Anna