Primary SMTP addresses are displayed incorrectly or secondary SMTP addresses are missing in Exchange Online

When you sync users to Exchange Online, the primary SMTP address is shown incorrectly as or the secondary SMTP address is missing. Depending on your configuration, this may cause mail routing issues and generate non-delivery reports (NDRs) for these recipients. 

For example, you receive an NDR that contains the following error message:

554 5.4.14 Hop Count exceeded – possible mail loop ATTR34
This occurs by design when you have one or more unverified domains in Office 365. 
To resolve this, add and verify the missing domains. For the steps to do this, see Add your users and domain to Office 365.

If this fix doesn't fit or work for your business needs, contact Support for further assistance.
Still need help? Go to the Office 365 Community website.

Article ID: 3173405 - Last Review: 07/01/2016 22:06:00 - Revision: 3.0

Microsoft Exchange Online

  • o365e o365m o365022013 o365 o365a KB3173405