[TSHOOT] – Exchange 2010 : 550 5.1.1 RESOLVER.ADR.ExRecipNotFound error message when you send email messages

By | 18 May 2017


Just a little post to troubleshooting an error in Exchange 2010 !

Last week, when i’ve a big problem with my exchange server, some users doesn’t send an email to the external address ! They receive this type of error :


Generating server: <server name>.local

IMCEAEX-_O=CONTOSO_ou=first+20administrative+20group_cn=Recipients_cn=<username>@<server name>.local

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

To resolve this issue, follow my explanations !

What is the problem ?

These issues may occur if one of the following conditions is true:

  1. You reply to messages that were migrated from personal folders (.pst) files or were migrated by using a third-party migration tool.
  2. The Outlook nickname cache (AutoComplete) contains a bad entry.
  3. The OfflineAddressBook is not updated or cannot be downloaded.

In my case it is the first condition, which triggered the second and maybe the third …


How to resolve the error RESOLVER.ADR.ExRecipNotFound?

To resolve these issues, follow these steps:

  1. Reset the nickname and the autocomplete caches in Outlook. Click the following article number to view the article in the Microsoft Knowledge Base: 287623 How to reset the nickname and the automatic completion caches in Outlook
  2. If you reply to a migrated message, type the whole email address of the recipient again. If the Autocomplete feature tries to input the recipient name or address for you, click the “X” to delete the entry, and then manually type the whole email address again.A screen shot of the To line, showing the auto-populated address and the
  3. Make sure that the Offline Address Book is operating correctly. For more information about how to troubleshoot the Offline Address Book, click the following article number to view the article in the Microsoft Knowledge Base: 2429946 How to troubleshoot the Outlook Offline Address Book in an Office 365 environment

You can download the .msi hotfix directly here , and don’t hesitate to contact me with a comments or by my contact page if you have any question about this problem.


If you like this post, don't hesitate to share it !

Leave a Reply

Your email address will not be published. Required fields are marked *