Compulsory stop on the motorway

I stayed on the track today with my Ommi. The whole thing went as follows: I am on the track with about 160 things, when suddenly without warning the speed drops to 0 and the car rolls out. At the same time the on-board compi reports “Automatic gearbox” and the indicator light of the motor electronics lights. Whether at this moment the engine was still running, I do not know, but the steering was still smooth. When I came to a stop slowly on the stand strip, the steering became weak. All attempts to start the engine again failed, and I could have been taken from the towing service to the fork. Does anyone have any idea what could be going on there? Before I have this checked in the workshop on Monday, it wouldn’t be bad if someone had a tip on what could come to me so that I wouldn’t get into a coma right away…