This means that the little locking bolts are not lining up with the sockets in the frame. You will have to adjust the door height in the frame. To do this you have to take the top caps off the hinges and adjust the height with the screw adjuster, usually a hex socket. There may also be another hex bolt in the side of the hinge which you have to loosen, and then tighten when you have done. Adjust all the hinges together, a little at a time, say a quarter of a turn, until the door locks. If the door needs raising you must turn the top screws clockwise looking at the top. It's fiddly but worth it.
TryingToBeUseful, April 2021
