Garage Door Disconnected from the Opener
Automatic garage doors can be disconnected from the opener. Although most garage doors are activated by electric openers, they can also open manually. This is why all electric operators have a release cord. It is used either in emergencies or when there is no power in the house and people need to open the garage door. It is also necessary during garage door repairs since it's best to work with the electric opener unplugged and disconnected from the door. In this case and when the door remains open for long, it's good to support the door with pliers or c-clamps to keep it from falling.
This means that the door won't be activated via the clicker or the wall button. So, if you find that the door won't move or make a sound when you press the clicker, check that it is connected with the opener. The opener is disconnected when the emergency release rope is pulled down and usually towards the opener unit. It will need a reverse movement to reconnect it.