This error message is a software error that occurs from time to time. It's technically the same as "Charging not possible - Visit workshop". Thankfully, it's easy to fix:
Make sure that the smart is not plugged in. Then lock it and wait 15 minutes. After the 15 minutes it forgot the error and works again as if nothing happened. If you want, you can bring it to the workshop, but they usually don't find anything.
If the error accrues more more often than 10.000 km, a new 12 V battery can solve the problem.
Note:
When you've got the monochrom display there's no text, only the control light of the motor is turned on.
