A small percentage of hangers are way too big to fit our motors and are thus not compatible. Only standard 5/16" (standard skate/longboard) trucks are compatible.
The motor axle has an opening with the following measurements:
Typically those with a very triangular or large square shape will not clear the motor axle or allow the wire to exit cleanly. The motor can touch the hanger but must be able to slide ALL the way in for the coupler to do its job and prevent rotation.
Make sure the motor slides all the way in and seats properly against the hanger. There should be at least a tiny amount of clearance all the way around the hanger as shown in this image.