The problem is with your safety "eyes" on your system. I bet the lights on the opener click rapidly once in awhile as well. Make sure that both lights on safety "eyes" sensors are on (one of them is amber and the other is green). If not, check the wiring onto the opener - white wire should go to white and gray to gray. This system will not operate properly if it cannot sense the proper functioning of the safety "eyes" sensors.
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The problem is with your safety "eyes" on your system. I bet the lights on the opener click rapidly once in awhile as well. Make sure that both lights on safety "eyes" sensors are on (one of them is amber and the other is green). If not, check the wiring onto the opener - white wire should go to white and gray to gray. This system will not operate properly if it cannot sense the proper functioning of the safety "eyes" sensors.