Why can't I change the targetangle on a hinge constraint with a script?

script.Parent.HingeConstraint.ServoMaxTorque = math.huge
script.Parent.HingeConstraint.AngularSpeed = 0.1


workspace.off.ClickDetector.MouseClick:Connect(function()
    script.Parent.HingeConstraint.TargetAngle = 0
end)

workspace.off.ClickDetector.MouseClick:Connect(function()
    script.Parent.HingeConstraint.TargetAngle = 100
end)

spawn(function()
    while wait() do
        print(script.Parent.HingeConstraint.TargetAngle)
    end
end)

It prints 0 all the time, even when I have clicked on the off part.