Coffee machine can't find brewing unit or you didn't install it correctly. If it's inserted ok it could be microswitches problem or anything wrong with transmission unit.
The unit may not be fully inserted. Remove it and see if the housing behind it is loose. It is held in by two screws. Tighten these with an Allen key and hopefully the unit will be properly seated when you insert it.
Answers & Comments
Coffee machine can't find brewing unit or you didn't install it correctly. If it's inserted ok it could be microswitches problem or anything wrong with transmission unit.
The unit may not be fully inserted. Remove it and see if the housing behind it is loose. It is held in by two screws. Tighten these with an Allen key and hopefully the unit will be properly seated when you insert it.