Sometimes your garage door will close on top of an object and the cable on that side will pop off.
How to fix a leaning garage door.
If your door rubs near the top or drags on the floor use a screwdriver not a drill to tighten the screws.
With a drill you re more likely to over tighten the screw and strip the screw holes or chew up the screwheads.
I don t know if this is the cause.
A friend tried pulling one corner in line and reinforcing with additional nails in studs but that did not solve the problem for the other corner.
Structure seems sound but one strut if that is what it is called has cracked.
A sagging garage roof a leaning garage or a garage in need of straightening can lead to other problems.
Garage is leaning so that garage doors cannot close.
Garage door crooked and the cable came off.
Safeway carpentry and doors has a great deal of experience in repairing and replacing garage roofs garage siding garage door openers garage doors and the concrete in and around a garage.