1. First of all, we need to check where the damage is. First, try it with the key to see if there is a problem with the lock tongue and cannot rebound. If it can't rebound, we can try to turn the handles on both sides to see if the handle is pressed down normally. If the pressure is normal, but the lock tongue does not rebound, there is a problem with the lock body, and a new door lock needs to be replaced directly.
2. But if the lock tongue can rebound when the handle is twisted, it is not a problem of the lock cylinder. It is necessary to check whether the door frame is deformed, such as the installation position of the lock body, or the deformation of the heaven and earth lock rod inside the door leaf, which needs to be debugged.