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Outlook Error: '550 5.1.1 faxnumber@faxmaker.com - User Unknown'

Overview

Outlook users are receiving non-delivery error messages when sending fax emails:

550 5.1.1 faxnumber@faxmaker.com User Unknown.
The e-mail address of the recipient was not found in the e-mail system of the recipient.

Or

Delivery has failed to these recipients or groups:

"5555555555@faxmaker.com (5555555@faxmaker.com) <mailto:55555555@faxmaker.com> The e-mail address you entered couldn't be found. Please check the recipient's e-mail address and try to resend the message. If the problem continues, please contact your helpdesk."

Environment

  • GFI FaxMaker
  • Microsoft Exchange 2003
  • Microsoft Exchange 2007
  • Microsoft Exchange 2010

Root Cause

The Exchange server was assigned authoritative rights to the faxmaker.com domain and it was looking in its own MailBox server for a user with the e-mail address "55555@faxmaker.com", and since it could not find one it was generating the non-delivery report.

In other words, if faxmaker.com is listed as an accepted domain in Microsoft Exchange Server 2007 / 2010 the Microsoft Exchange Server starts to search for the local recipient faxnumber@faxmaker.com instead of delivering the fax email request to the GFI FaxMaker server.

Resolution

  1. Open the Exchange Management Console and expand Organization Configuration.
  2. Select Hub Transport and click on Accepted Domains.
  3. Remove Faxmaker.com and FAX Domains.
  4. Click on Send Connectors.
  5. Right click on the internet of Default connector and go to Properties.
  6. Select the Address Space tab.
  7. Click on the "SMTP *" address and click on Edit.
  8. Change the cost for the (*) domain to 5.
  9. Click twice on OK to Close.
  10. Check the GFI Faxmaker send connector Address Space cost and ensure that is set to 1.
  11. Some servers will require the Exchange Transport service to be restarted in order for the changes to take effect.
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  1. Priyanka Bhotika

  2. Posted

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