Article ID: 2730609 - View products that this article applies to.
Not sure what release of Office 365 you're using? Go to the following Microsoft website:
Am I using Office 365 after the service upgrade?
You have an Microsoft Exchange hybrid deployment in which cloud-based users in Microsoft Office 365 and on-premises users have the same email namespace (such as firstname.lastname@example.org). However, on-premises users aren't getting email messages from Office 365 users.
Additionally, when an Office 365 user sends an email message to an on-premises user, the Office 365 user receives a nondelivery report (NDR) error message that resembles the following:
#550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found ##
This occurs if the domain that's set up in the hybrid deployment isn't set as a shared domain in Office 365. To fix this issue, set up the domain as a shared domain. To do this, follow these steps:
Use Exchange Admin Center if you have Office 365
Use Exchange Control Panel if you have Office 365 pre-upgrade
The Exchange Admin Center and the Exchange Control Panel lists the domains that you added to your account through the Microsoft Office 365 portal. It lets you manage how messages are delivered. In a hybrid scenario, Exchange Online must be set up correctly so that when a cloud-based user sends an email message to an on-premises user, Exchange Online routes the email message to the on-premises messaging environment.
For more info about accepted domains, go to the following Microsoft TechNet website:
For more info about hybrid deployment, go to the following Microsoft TechNet website:
Exchange Server Deployment Assistant
Still need help? Go to the Office 365 Community
Article ID: 2730609 - Last Review: September 11, 2013 - Revision: 10.0
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