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Users in the on-premises environment are not receiving mail from Office 365 users


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Symptoms

Consider the following scenario. You configure a mail coexistence scenario in which users in the online environment in Microsoft Office 365 and users in the on-premises environment use the same email namespace (such as alias@contoso.com). However, users in the on-premises environment are not receiving mail from Office 365 users. And, when an Office 365 user sends an email message to an on-premises user, the Office 365 user receives a non-delivery report (NDR) that states that the recipient is not found.

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Cause

This occurs if the domain that is configured for coexistence is not set correctly as a shared domain in Office 365.

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Resolution

Configure the domain as a shared domain. To do this, follow these steps:
  1. Sign in to the Office 365 portal (https://portal.microsoftonline.com) as a global administrator or a service administrator.
  2. Click Admin, and then under Exchange Online, click Manage.
  3. In the Exchange Control Panel (ECP), click Mail Control, and then click Domains & Protection.
  4. Select the domain that is configured for mail coexistence, and then click Details.
  5. Select Shared, and then click Save.

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More information

The ECP lists the domains that you added to your Microsoft Online Services account through the Office 365 portal. And, the ECP lets you manage how mail is delivered. In a mail coexistence scenario, Exchange Online must be configured correctly so that when a user in the online environment sends mail to a user in the on-premises environment, Exchange Online routes the mail to the on-premises message environment.�

The Microsoft Online Services Directory Synchronization tool keeps your local Active Directory Domain Services (AD DS) synchronized with the online directory. It synchronizes users, contacts, and groups, and these entities are displayed in the global address list in Exchange Online. Users in the online environment do not know whether other users are online users or on-premises users. Therefore, you must use the ECP to correctly configure domains so that on-premises users can receive mail from online users.

Shared domain (mail coexistence) Hosted domain (online only)
The on-premises messaging environment is authoritative.

If an online user sends an email message to a user who is not in Exchange Online, the message is routed to the Internet and delivered through MX records. No NDRs are generated in this scenario, assuming that the recipient has an on-premises mailbox.
Exchange Online is authoritative.

If an online user sends an email message to a user who is not in Exchange Online, Exchange Online generates an NDR and does route the message to the Internet for potential delivery.



For more information about mail coexistence in Office 365, visit the following Microsoft website

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Keywords: KB2510049, vkbportal230, vkbportal237, o365, bposs, vkbportal231

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Article Info
Article ID : 2510049
Revision : 9
Created on : 6/21/2012
Published on : 6/21/2012
Exists online : False
Views : 73