U9.LD Entrance lock and unlock

"Suddenly the front door couldn't be unlocked."

I can't unlock it from the inside, so I want you to open the front door.I receive an explanation of the situation, but I still don't understand by phone.

It's a normal entrance to the U9 double lock.However, when I try to open it, the lever does not go down.I can see the latch bolt, but there is no movement.

No thumbturn unlocking from the doorscope is required.Since there is a client inside, I received the key through the post and tried to operate the cylinder, but it is normal operation.With a little manipulation of the latchbolt, the door is unlocked, and the front part is gone.

This causes the latch bolt to rotate and wobble. If you turn it 90 degrees, you're in big trouble.

I received a front desk that was not from the client.I re-fixed it with new screws and I was done.

It seems that he made a mistake in the operation method of the double lock.He said he was in a hurry and couldn't tell which one was locked.