Simscape Multibody/Simulink: How do you check for the number of degree of freedom of a revolute joint block?

Im simulating a swing door with attached generator using simscape/simulink. I imagine there will only be one input for the door to open, which is the input force in the knob. I assembly the system but the revolute joint (SwingMotion) connecting the door and the hinge has this error:

"In the dynamically coupled component containing Revolute Joint 'SwingingDoor/Swing Motion', there are more joint primitive degrees of freedom with automatically computed force or torque (4) than with motion from inputs (0). In general, the equations of motion do not have a unique solution. Solve this problem by increasing the number of joint primitives with motion from inputs or reducing the number of joint primitives with automatically computed force or torque. Resolve this issue in order to simulate the model."

The actuation of all the revolute joints are set to automatically computed, as they have no torque input. I dont quite understand why i get the problem in my assembly. I hope someone can help me resolve this error.