The following non-delivery report:

Your message did not reach some or all of the intended recipients.

None of your e-mail accounts could send to this recipient.Your message did not reach some or all of the intended recipients

The Diagnostic information for administrators section also contains the following error:

#550 5.4.4 ROUTING.NoConnectorForAddressType; unable to route for address type

The NDR contains a mailto link with the recipient's address. You might get this NDR if you send an email to this address.

To resolve this issue:

  • Delete particular nickname cache entry
  • Fix the type of the recipient's contact email:
    • Outlook 2007:
      1. Open New Email and add the recipient's name in the To field.
      2. Double-click the email address and change the Email type to SMTP:
        Internet type SMTP
      3. Send this new message.
        Note: If you don't send a message after making this change it will revert back once the mail message is closed.
    • Outlook 2010:
      1. Open New Email and add the recipient's name in the To field.
      2. Double-click the email address.
      3. Click View More Options to interact with this person and select Outlook properties:

        Outlook Properties
      4. Change the Email type to SMTP:
        Internet type SMTP
      5. Send this new message.
        Note: If you don't send a message after making this change it will revert back once the mail message is closed.
    • Outlook 2013:
      1. Open New Email and add the recipient's name in the To field.
      2. Double-click the email address.
      3. If the email address is not added as a contact, Outlook Properties window will open. If the email address is added as a contact, the contact card will open. Double-click the email address in the contact card
        Double-click the email address
      4. Change the Email type to SMTP:
        Internet type SMTP
        Note: if you cannot see the Outlook Properties option, you need to modify the registry as described in the following article: E-mail properties for contact addresses in Outlook 2013
      5. Send this new message.
        Note: If you don't send a message after making this change it will revert back once the mail message is closed.