Getting NDR from Internal mail address.

Question

We have exchange 2013. we are getting NDR from internal users from outlook. OWA is working fine, we are facing issue only for outlook.

And we have checked offline address book. offline address book is working properly. and we have also check after creating new outlook profile but we are facing same issue.

Answer 1

Try clearing the autocomplete cache:

https://support.microsoft.com/en-us/office/manage-suggested-recipients-in-the-to-cc-and-bcc-boxes-with-auto-complete-dbe46e31-c098-4881-8cf7-66b037bce23e

Is this happening for one use or all?

Answer 2

Hi,
Is there any Diagnostic information for administrators under the NDR message? If there's information like below, you should add the correct X500 address to the sender's email address(ADUC-Users-username-attribute editor-proxyaddresses):

Generating server: EXCHANGE-SERVER.somename.domain.com  
IMCEAEX-_O=FIRST+20ORGANIZATION_OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+28FYDIBOHF23SPDLT+29_CN=RECIPIENTS_CN=******@domain.com  
#550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found ##  

- Replace any underscore character (_) with a slash character (/).

• Replace “+20” with a blank space.
• Replace “+28” with an opening parenthesis character.
• Replace “+29” with a closing parenthesis character.
• Delete the “IMCEAEX-” string.
• Delete the “@xyz .com” string.
• Add “X500:” at the beginning.

Another solution you can try is asking the problematic user to reply to a message from those users who he can't send to, see if the problem solved after that.

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