That building is inactive. Either your plan set it aside because you have more buildings than it allows, or someone made it inactive. It refuses only new bookings.
What still works
- You can still set up and manage its floors and rooms.
- Its existing bookings carry on as usual.
- New bookings are refused until the building is active again.
- Go to Buildings and find the building marked Inactive.
- Make it active again.
- If your plan has no room left, first make another building inactive, or upgrade your plan.
Good to know An inactive building is never deleted. Its rooms and booking history stay as they are.