When you add a new domain in the Office 365 portal in Microsoft Office 365, and you create users or change existing users to use the new domain, email messages aren't received for the new domain.
This can occur if one of the following is true:
The domain has to replicate to all Microsoft Exchange Online servers. This could take up to one hour.
The appropriate MX record doesn't exist or has to replicate to all applicable Domain Name System (DNS) servers around the world. This could take up to 72 hours.
To fix this issue, follow these steps:
Make sure that the new domain is verified in the Office 365 portal.
Make sure that the MX record for the new domain points to the value that's listed in the DNS Settings section of the Office 365 portal for Exchange Online. For more info, go to the following Microsoft website: