Connect joystick and controller...to ROV gripper

I just received my joysticks and controllers:

SyRen 10A 6V-24V Regenerative Motor Driver (RB-Dim-04)

2 Axis Joystick (RB-Sct-283

Connected and working (analog). However, when gripping pressure is applied (ie. grasping an object) it stalls and cannot be reversed unless pressure is released. Not sure what to do.
As you can tell, I’m new at this…this is for my grade 9 students…building an ROV.

There might be a setting in the motor controller for over-current.
Usually you would want to stop it before going that far as you might break something.