The courtyard wall of my old house fell down for no reason last night. What's the story?

Personally, I feel that you are superstitious. You said yourself that this is an old house. The old houses in your hometown are usually headed by those people. They will be unstable after a long time, and if it rains for a long time, and so on, external factors may affect them, so I don't think you should think too much about it yourself.