Start by checking your battery is charged and connected to your e-bike properly. Make sure that the connectors are clear of debris and are dry.
If you're sure your battery is charged and installed on your e-bike in the correct way, check any visible cables and connectors from the battery and the rest of the e-bike. If your e-bike has a screen, check it for visible damage. Check the connection around the motor to see if the cable has come loose.
If everything appears normal and the battery is charged, please let us know here so we can resolve the issue.