If anything interrupts this beam of light the garage door will not close and the ceiling light on the opener mechanism will flash as mentioned in the previous step.
Garage door opens but does not close with remote.
To solve the problem identify the source of the radio interference and either move it or turn it off.
This is the reason the garage door remote can open the door but may not be able to close the garage door.
This is one of the sensors.
If the door opens when you press the button on the wall mounted control keypad but not when you use the remote you might have just pinpointed the source of the problem.
If they are working correctly the problem might be because of the safety sensors.
Check the area around the sensors to make sure nothing is blocking the sensor.
One sends a beam of infra red light to the other.
The problem is often intermittent.
Try resetting the remote.
To test trigger the remote while standing close to the motor unit if the door opens consistently from that close distance interference is likely the problem.