Hi and
to the forum.
I would start by checking the voltage readings from the three hall sensors:
Connect your battery pack and locate the motor connector with the five thin wires, and then place your black meter probe into the black connector and then check for a supply voltage for the hall sensors on the red connection, which I expect will be ~5V.
Assuming the 5V feed was correct, leave the black probe touching the back wire contact and place the red probe into one of the signal wires from the three hall sensors
(typically Blue, Green and Yellow) and then rotate the wheel very slowly by hand. The voltage should alternate between ~5v and 0V.
Repeat this check on the other two hall sensor signal wires.
If all three signal wires produce an alternating high/low voltage
(when the wheel is turned slowly) then the hall sensors are working correctly, in which case you will need to carefully check all connections between the motor and the controller to ensure they have not been connected incorrectly.
It might also be worth temporarily unplugging the brake switch connector to see if it makes any difference.
Alan
