hi, so the reason the registration number was being blocked was that the address that i gave the city of new york did not match the one on my listing (the listing did not mention the unit number).
i called airbnb repeatedly about changing this but only was able to reach customer service representatives who were wholly incapable of helping me with my problem!
i then proceeded to send an email to airbnb support and that's when finally i started receiving help. calling airbnb support on the weekend also gave me more capable people. so i would suggest, whatever problem you're dealing with don't call, write!!!