Genius!! I did as discribed above (roof was stuck in vent position, with the back half opened, but strangely enough I was able to close it when car was moving...)
followed steps above, repositioned the back part. after that all worked fine, did reset of the roof (60 seconds holding the button and let it run through all its setting, till all is closed) but roof didnt fully close (2 cm opening) took out rubbery wind protections (don't know what they are called) on the inside on the right and left when roof in vent position. closed the roof and slightly undid the four (2 on each side) trax screws. Pushed the roof up a bit, and retightened the 4 screws. Perfect now!!
Very happy! thanks a lot!!