When you add a comparable by URL, we upload it to our servers and check it against all of the listing data we collect every day. A few things can go wrong–here's a list:
Duplicate Comparable: If you've already added that URL, we won't add the same listing again to the same unit.
Not in URL format: If it's not a URL format (e.g, www.airbnb.com/rooms/12345456) we can't add it. Please check your URL and try again. Note: you do not need to include the http://, https://, or even www. It's fine if you do include it, we'll just strip it all out.
Not supported URL: Usually when the system says a URL is "not supported" that means that it's a valid Airbnb URL, but that listing may no longer be published on Airbnb. It also may be a URL outside of our coverage area. Check again and make sure you've got the right URL.