Does the rotor move if you shake the watch vigorously? I would open the case (carefully, do not leave scratches on the case back, it's very easy unfortunately), check if there are screws on the movement holder blocking the rotor (or screws sitting too high), if that's not the case, remove the rotor (there's a screw keeping the rotor in place) and put it back. It's a super easy task but again, be careful not to mark the caseback.