New site mailbox has an incorrect email address


Consider the following scenario in Office 365:

  • You have the following domains:
  • and are accepted domains that were added to the Hybrid Configuration wizard. is federated and can't be set as the default accepted domain in Office 365. Therefore, shows as the default domain.
In this scenario, a new site mailbox is assigned an incorrect email address.


To resolve this problem, change the email address of the site mailbox. To do this, follow these steps:

  1. Connect to Exchange Online by using remote PowerShell. For more information, see Connect to Exchange Online using remote PowerShell.
  2. Run the following command:
    Set-Mailbox -Identity MySiteMailbox1 -EmailAddresses, -EmailAddressPolicyEnabled:$False 


Still need help? Go to Microsoft Community.

Article ID: 3172620 - Last Review: Dec 29, 2016 - Revision: 1

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