Wife called me this evening said garage door will not open. I looked at it this evening. Lift master elite. The cable pulley is attempting to pull the door up but it looks like it is ripping the door off at the top. Top of door is flexing and bending. I can manually move the door up and down. I can not tell where it is sticking if it is a tract problem. Where do I look for the problem? Worked fine this morning.