This could and most likely is because the photo eyes (synced to your Garage Door Opener) are out of alignment. Your photo eyes must be facing each other at all times in order for your Garage Door to operate correctly. Sometimes homeowners accidentally bump them with garbage cans, rakes, shovels or other objects and don’t even realize it. Shortly after when the homeowner goes to close the Garage Door, it will only close about 4-6 inches and goes right back to open. Simply turning them towards each other can realign the photo eyes. Make sure that the light on each eye is lit solid and not blinking. Once you have done this, the Garage Door will function properly once again.
Pictured here are what your photo eyes may look like. A solid light indicates your Garage Door Opener is working properly and your Garage Door will open and close. A blinking light indicates there is a problem and your Garage Door Opener will not function correctly. In this case you should refer to the above or call a professional like D & D Garage Doors (if in the state of Florida).