Exchange Server NDR Report after mailbox migration - IMCEAEX Error - NDR 5.1.1

Exchange Server NDR Report after mailbox migration - IMCEAEX Error - NDR 5.1.1

Importance of X.500 Address:

Distinguished Name (DN) works similary when you move a file test.txt to different folder (for example, c:\orgname\sitename\recipients\temp.txt) . If you moved an object it would get a new DN, just like if you moved this file to another folder it would become c:\orgname\sitename\recipients\temp\test.txt. Hope now the similary logic is applied to the below format

x500:/o=/ou=/cn=Recipients/cn=

Or perhaps you've seen the attribute below on an object in the AD:
legacyExchangeDN:/o=/ou=/cn=Recipients/cn=

Error Message:
IMCEAEX-_O=mycompany_OU=First+20administrative+20group_cn=Recipients_cn=raji@test.com #550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found ##

Solution:

When there is change in LegacyExchangeDN the value in OWA or Outlook autocomplete cache not able to deliver email and it result the NDR 5.1.1

Remove the auto-complete cache file as follows

• New mail 
• Type in the first characters of the failed address 
• Delete all entries of the failed address via ‘DEL’, scrolling up/down via the arrow keys 
• Type in the address again or select it from the GAL via the ‘to’ field 
• Send the mail.

Try to send email again if still issue persist then follow the below step

Corrupted Address:

IMCEAEX-_O=MMS_OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+28FYDIBOHF23SPDLT+29_CN=RECIPIENTS_CN=User6ed4e168-addd-4b03-95f5-b9c9a421957358d@mgd.domain.com

•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 "IMCEAEX-".
•Delete "@mgd.domain.com".
•Add "X500:" at the beginning.

Correct Address:

X500:/O=MMS/OU=EXCHANGE ADMINISTRATIVE GROUP (FYDIBOHF23SPDLT)/CN=RECIPIENTS/CN=User-addd-4b03-95f5-b9c9a421957358d

Ref: http://support.microsoft.com/kb/2005644/EN-US