Diagnosis
The safety reversal system is triggering. The most likely cause is misaligned infrared safety sensors.
How to Fix It
Check the sensor alignment. The amber LED on the receiving sensor should be solid, not blinking. Loosen the sensor brackets. Align them precisely so they point directly at each other. Tighten. Test.
If That Didn't Work
The down force limit is set too low. Increase the down force adjustment screw on the opener head. Turn it clockwise one-quarter turn. Test. Repeat until the door closes fully.
Heads Up
Never bypass the safety sensors. A misaligned door track or binding roller can also cause reversal. Check for obstructions in the track first.