Most of us only think about our garage door when its not working. The most common problem is usually self inflicted with bumping or blocking safety sensors. A little about sensors first they must always stay clean and dry. the mounting of sensors is many times on the track of the garage door. If your garage door starts having issues rolling it can shake the track causing the door to reverse. A quick view of you safety sensors will determine if they were installed properly no more than 6” from the floor. The lights should be able to be seen from inside the garage if they are both on then they are communicating. below I am adding some reference pictures. If your door does return open on its own and the lights flash the opener is having safety sensor communication issues as explained above. Last resort once you have made sure the opening is clear you can Bypass the sensor by holding down the wall button until the door is completely closed.This is a Last resort only. If in doubt call your friendly garage door technician he can adjust the sensors and address any mechanical or safety issues your door may have.