I know someone that has had this. Ended up being a loose connection. Check all the wires to the motor are fully plugged in.Today I had the first problems with the motor. After about 20km the motor suddenly stopped, switched on again, after 10 meters it stopped again. Battery out, waited a bit, back in. After a km again the same. I then made my way home, but on the last 5km the motor wouldn't turn on at all. At home I was able to switch it on again, made a diagnosis with the app, everything is green, the battery has a 40% charge.
Has anyone had such a problem?