Import a calendar from an external website

Hi folks,


On our website, we have a bespoke ical reservation calendar. Airbnb can import this calendar without any problem. When I try adding it to Booking.com on the “Synchronise your calendars with Airbnb, VRBO, and more” page, the status stays on Activating. I have also tried removing the link and adding the export link from Airbnb, but I get the same result, that is, status = Activating. 


Could I have missed a step? Any advice welcome.