@Mary769 where did you post the email they responded with?
I see a post that might be a summary of what the email might have said, but I don't see the actual text of an email from AirBnB.
Could you post the actual email you received?
I know your listing is not able to take bookings for guest check-in on the same day another guest checks out, but I don't think it is a company-wide policy.
Case in point:
My current guest (the one that is here with me right now) made their reservation Feb 1 (well after the January 2018 deadline). Their check-in date was Feb 3. The prior guest was scheduled to check out Feb 3, that same day.
Plus, as I mentioned, 9 out of our 10 guests in February check in on the same day someone else checks out. Many of these bookings were made in 2018.