I'm having the very same issue with my Rad Rover 6 plus currently. Brakes have been ruled put as I've replaced them with different ones that do not connect into the system. Only solution I've had so far is turning on the bike while pedalling or throttle but as soon as I stop it won't output power again.
Let me know if you found a solution! Rads solution is send me all the parts - which are out of stock.
Let me know if you found a solution! Rads solution is send me all the parts - which are out of stock.