Why do I get the error 'The recipient's e-mail address was not found in the recipient's e-mail system' when sending message to the valid recipient? Print

When sending message to the valid recipients using Outlook you may receive the following bounce back:

Delivery has failed to these recipients or distribution lists:

'Contact_Display_Name'
The recipient's e-mail address was not found in the recipient's e-mail system. Microsoft Exchange
will not try to redeliver this message for you. Please check the e-mail address and try resending
this message, or provide the following diagnostic text to your system administrator.

Diagnostic information for administrators:

...
#550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found ##

It can be caused by the following:

1. Outlook nickname autocomplete cache has an incorrect record for this name. To verify whether the nickname cache is causing the issue, please try to send the same message to the same recipient using Outlook Web Access. If the message goes through you should follow the steps listed in the article below to clear nickname autocompletion cache:
   How to reset the Outlook nickname autocompletion cache
2. You replied a message imported from another mail system and having internal reply to address. The resolution is to type the email address manually.
3. The outlook contact is corrupt. Please check the address listed in the contact.