Terraria Housing No Longer valid

Okay so I have no idea why this is happening, and it’s getting really frustrating. On console for Xbox One, for some reason the housing in the house I’ve made for my NPCs are becoming not valid one by one. It can’t be corruption/crimson because it’s not even the first floor that’s affected, it’s the second and third floor that are affected! I haven’t changed the rooms at all, yet they’re kicking the NPCs out because of this. I’ve attached a picture to show which 4 rooms are no longer valid, and numbered them to show what order they became no longer valid. This has taken place over the course of around 15 hours of gameplay.

Solution 1:

Use the ? option in the housing menu, which will tell you what's wrong.