Question : mail rejected because your IP is in DUL

Getting this error when trying to send an email to a certain Domain.
>>>>
mail rejected because your IP is in DUL
>>>>>

I confirmed that they implemented MAPS Messaging Labs.

Do I supply my domain name so that they can whitelist? ex. [email protected] (that is, mydomain.com)

Or

Do i supply them with my static public IP address for my network so that they can whitelist all emails from my Exchange server?

Thanks in advance

Answer : mail rejected because your IP is in DUL

Nevermind, the domain was sufficient enough and now I am able to send to their Domain.