Having the same problem, was wondering if you found an answer. I also noticed that my belt, track, whatever is out of alignment. I am wondering if it is some sort of safety thing if the track is off line.
see the video attached, Lube the rollers bearing too Front+back. However you must test the main motor, measure the input voltage terminal at motor, if there ARE AND THE motor NOT run the motor is faulty. 2) test the output voltage terminal control board, for input voltage motor, if there ARE NOT the board is faulty. see the diagram attached.
You need to tension the belt .Turn the machine on and up to 4 kph or 3 mph.Stand on the side rail with 1 foot and try and stop the belt with the other. If you can stop at all tighten the rear roller with the allen key provide with the machine. Turn it on both sides clockwise 180 deg whilst machine is still running. If still loose tighten another 90 deg.