Turn the black knob by hand
The lock does not open automatically. You have to turn the black knob.
Turn in the appropriate direction
Depending on your door you have to turn to the left or to the right. Check the picture below for your situation.
Door can be jammed or stuck a little bit
Sometimes the doors are a little bit jammed or stuck. It helps if you pull the door handle towards you and then turn the black knob. Remember you have 15 seconds, so all the time in the world. You can put your phone in your pocket and then open the door.