In some cases, due to the gravity of the door leaf, or the cause of the door leaf, the door leaf sinks, and the door is locked or the door is not smooth. At this time, it is often difficult to open the door with a key and lock the door. At this time, do not forcibly twist the key, so as not to break the key and increase trouble.
The correct solution: you should first check the reason. If the door leaf sinks due to loose leaf, the loose leaf should be fastened with screws. If the door frame is deformed or its cause is unrecoverable, start with the door frame and expand the lock tongue accordingly, so that the door lock switch door can resume normal and smooth.