If the transmission mechanism of the lock body cannot drive the lock tongue to rebound, the lock body should be broken and the lock needs to be replaced. If the shaft wheel of the lock cylinder cannot drive the lock body, resulting in failure to rebound, this should be a problem with the lock cylinder. Just replace the lock cylinder. The precautions for door lock shall be judged first. If the latch cannot rebound, the lock body should be broken and need to be replaced. If the lock cylinder can not drive the lock body, there should be a problem with the lock cylinder and the lock cylinder needs to be replaced.
If the lock cannot be opened due to external force, the lock tongue may be decoupled, or the shape of the lock tongue may be distorted, and the screws fixing the lock tongue may fall off, resulting in the door being stuck. At this time, find the lock tongue and pull the fallen screws back for positioning.
When the tried methods are useless, you can find a special unlocking company. These companies generally have a professional team to solve the unlocking problem. （SuoSheBuNengSuHuiMenDaBuKai）