Airbnb make it clear that if you receive a booking request you must accept or decline within 24 hours or they will block the dates in your calendar.
If you have an inquiry you simply need to respond.
Was it a request or inquiry? Did you send the pre-approval within 24 hours?
Airbnb says on its help centre “you can decline any booking enquiries or reservations that you can’t accommodate, but you should do so within 24 hours”.