Locked indoors and unlocked due to door chain malfunction

"Door chain malfunction locked and unlocked"

Central and South American?Are you Indian?They seem to understand Japanese, but they can't seem to explain it well.

It looked like a thumbturn with a button that couldn't be opened from the inside, but it turned out to be a door chain.

As long as I checked through the gap in the door, there didn't seem to be any problems, but I was told that I couldn't reach the top and couldn't press the buttons.

The screws on the stile side are hard, but I can only feel them slipping.In the end, I decided to remove the screws on the door side.One was hard and I had to remove three to unlock it.I reassembled it and couldn't find any problems.