A magnet is interfering with the torque sensor.
Your drive unit is detecting a magnet on the pedal, which is interfering with the torque sensor. As a result, the drive unit cannot provide motor support.
Solution steps
Check whether there is a magnet fixed in the proximity of the drive unit, e.g. on the pedal or crank, and remove it. Then restart your eBike. If the problem persists, please contact your specialist dealer.