Unlocking the post lock of an apartment house

"I can't open even my PIN"

Certainly it doesn't open even with a PIN.The mailbox was full of luggage. I can't get DD well.I can't tell what's causing it.

There is a cardboard that seems to be forcibly posted.It seems to be obstructing the back of the dial lock.

"Would you like to take out the luggage inside?"

When I turned to the back side and took out a large cardboard compact stool from the gap, DD was taken well.

But I can't open it even with my PIN.I tried search unlocking again, but got a different PIN.I don't know the cause, but it's done by telling the correct PIN number.