notification callback

Hi, we changed server provider yesterday, and now we're not getting the notification callbacks. We already changed the DNS and we confirmed that it's pointing to the right box. Do you guys need to bind the address to a specific IP? If so, the new IP for our api is 209.166.133.108. The URL we have set up for notifications is "https://api.boardbookit.com". Our company is BoardBookit. Please help as soon as possible as we are currently live and we need the notifications to work. Fernando