Ensure the door isn't in "Vacation" or "Lock" mode when it won't respond to the remote from the outside. When in one of these modes it may open once using the remote, then must be unlocked from the wall control inside the garage. Click the remote as you are standing under the box but can still see the top. If you can see that the red light on top is blinking, it means that the battery is fine and that the problem exists somewhere else in the system. Check the battery in your