Some (but not all) of my users are getting the following NDR when trying to email a user: Fred Jones 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. IMCEAEX-_O=EXCHANGE_OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+28FYDIBOHF23SPDLT+29_CN=RECIPIENTS_CN=Fred+2EJones@domain.com#550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found ## Fred Jones (fred.jones@domain.com) is a valid address though which is strange. And, like I said, some users can email him fine. Can anyone shed any light on this? Running Exchange 2007/ Outlook.

On Tue, 15 Feb 2011 22:09:03 +0000, Sheen1990 wrote: > > >Some (but not all) of my users are getting the following NDR when trying to email a user: > >Fred Jones 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. > >IMCEAEX-_O=EXCHANGE_OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+28FYDIBOHF23SPDLT+29_CN=RECIPIENTS_CN=Fred+2EJones@domain.com#550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found ## > >Fred Jones (fred.jones@domain.com) is a valid address though which is strange. And, like I said, some users can email him fine. > >Can anyone shed any light on this? Running Exchange 2007/ Outlook. Was his mailbox deleted and then recreated? The "ExRecipNotFound" says that the legacyExchangeDN used to send the message is unknown. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Hi Sheen1990, Any update for your issue? Rich gave some good information, so we could delete the cach for the special user email address, or we could remove the nk2 file, or we could add the legacyExchangeDN as a X500 address on the mailbox. Regards! GavinPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.