Does the light on the motor on the ceiling flash a few times ? Is it a Sensor problem?
Scenario 1: Your door goes down, but not all the way and comes back up!
Helpful Hint: Toward the bottom of the two vertical tracks there are 2 separate sensors with photo eyes facing each other to maintain a solid beam across while the door is coming down. If this beam gets interrupted for whatever reason the motor assumes there is an object in the doorway so the door goes back.
Commonly this beam gets thrown out of alignment when it gets moved/pushed accidentally , this can be fixed by adjusting it finely (i.e. moving it gently by hand), until you get the lights the green and the orange solid and steady again.
Both lights must be ON must be solid and bright – no flicker or blink and that is when you know the sensors are aligned.
Scenario 2: Sensors are perfectly aligned and you are still having the same problem.
As the door is coming down at a very specific spot along either vertical tracks due to a mild bump, weak structure or just a loose jam bracket, the track gets pushed outward and throws the beam out of alignment. Framing around the door (garage structure) and all the tracks hardware need to be checked and reinforced. This is a job for Doorman Garage Service