@Chris232:
I have found that some platforms are unable to use the Airbnb calendar link. Two options:
1. Bring the Booking calendar into Airbnb instead and then update the Booking calendar manually for an Airbnb reservation.
2. If you use a third platform, say VRBO, then sync that calendar using the Airbnb link and then send the third platform's ical link to Booking. Double to check to make sure it is working since all of Booking's reservations are instant book.
BE AWARE! We tried Booking last fall and received three reservations, two of which were already booked days and the days were definitely marked out on the Booking calendar. We cancelled our account but Booking really hassled us about it.