garage door won't close all the way it opens back automatically

by mey
(greenwich CT)

use remote control or control panel switch to open.

the door goes down and almost reach the bottom. but it won't close and suddenly is going up again. So we could not close the garage door.

I think it related to safety sensor.

please let me know how to solve the this problem.

Thank you.

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Is anything hanging from bottom of door that may be swinging into path of safety beam? Clean lenses of safety sensors.

If not, check your openers limits settings. Check for obstructions. Try disconnecting the opener to see if door closes freely without binding.