the sunroof is not "just off track". be glad this happened with the sunroof closed because if it was open, you would have to fix it. once you find a diagram of the sunroof, you will begin to appreciate how complex the drive mechanism is. if the tracks are clear, the first step is to remove the headliner (3 hours) to diagnose the problem. as a MB shop, I have never had a 124 or 126 owner repair the sunroof for that reason.