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.
- 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:
- You may have to wait up to 72 hours.
- Set up a hybrid deployment. For more info, see the Exchange Server Deployment Assistant.
For more info about mail flow setup options in a hybrid deployment, see the following Microsoft resources:
- For on-premises Exchange 2013: Transport Options in Exchange 2013 Hybrid Deployments
- For on-premises Exchange 2010: Understanding Transport Options in Exchange 2010 Hybrid Deployments
- Set up forwarding to the Office 365 users' Microsoft Online Email Routing Address ([domain].onmicrosoft.com). For more info, see Forward email to another email account.
Article ID: 2415053 - Last Review: Dec 16, 2016 - Revision: 1