If you have an automatic garage door, you may be able to repair it yourself. If not, seek out a professional.
Step 1 – Check the sensor
The first thing you will want to do is check the sensors on your door. This can be done by pressing down on the sensor while closing the door manually. If the door stops when you press down on it, then this means that your sensor is working properly. If not, then you may need to replace it with a new one.
Step 2 – Check for obstructions
Another thing that can cause your garage door not to close properly is if there are any obstructions in front of it. For example, if there is something in front of your garage door such as trash or leaves, these items may get caught in the tracks of your garage door making it difficult for the system to close properly. To fix this problem all you need to do is remove these items from in front of your garage door and then try closing it again.

Check for dirt or debris on sensors. Dirt and debris can cause interference with sensors, so if your door has stopped closing all the way, make sure there isn’t any debris in front of the sensors. If there is dirt or debris on them, clean them off with a soft cloth dipped in warm water and then dry them thoroughly so they won’t short circuit again.
Test sensors by manually closing the door by hand. Make sure that all four sensors are connected properly and aren’t damaged before proceeding to step three below. If one or more of your sensors are damaged or disconnected, they will need to be replaced by a professional (see “Replacing Sensors” below).