The first thing I would do is check the connectors between the motor wires and controller wires to make sure they are properly connected and in good condition. I would unplug the connectors and look at their pins to make sure none of the pins are bent over. Then I would inspect the motor wires for any possible damage. Brushless motor wires are especially susceptible to breaking or having their insulation worn off where they exit the center of the wheel axle because the axle usually has sharp edges and the wires have to make a sharp turn in that area.
Please let me know how it goes.
Jon forwarded me the support ticket that you submitted and I read that you load tested the new batteries and they passed the load test and are good. Otherwise load testing the new batteries is what I would recommend next.
Considering that the hub motor wires and connectors are in good condition that points towards either the hub motor or the controller being faulty. Both brushless motors and brushless motor controllers are too complex to easily test unless you have a second identical vehicle to swap the motor and controller in between from to determine which part is not working.
Controllers are usually the weak link in the system so if I had to make a decision between replacing the motor or controller I would choose the controller.
Please let me know if you have any questions.