unity rigidbody constraints not working code example

Example: unity rigidbody constraints

m_Rigidbody = GetComponent<Rigidbody>();
        //This locks the RigidBody so that it does not move or rotate in the Z axis.
        m_Rigidbody.constraints = RigidbodyConstraints.FreezePositionZ | RigidbodyConstraints.FreezeRotationZ;