Angle Driver error

I am trying to constrain the angle between of a body relative to another body(they are attached by revolute joint) in my model. Currently I have an angle driver (unactuated) attached to a ground and one of the bodies. I keep getting an error that says

 'The two axes in this angle driver are aligned, within tolerance. The motion is singular. The angle between these axes cannot be zero.'

I have tried using the same values for CS and fixed axis inputs as in the mech_angle_unact file from the Help pdf, but I keep getting the same error. I have also tried resetting the tolerance in the Config_parameters window. What am I doing wrong?