Article ID: 2730609 - View products that this article applies to.
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:
The Exchange admin center 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