We just moved from a SBS 4.5/Exchange 5.5 server to SBS 2003/Exchange 2003 with a new server name. The user accounts were created manually on the new server. User PCs were upgraded from Outlook 2000 to Outlook 2003, then connected to the new server. Email was imported to the new Exchange 2003 server using Outlook 2003from pst files. Replying to preconversion emails fail with NDR. Same as described here: NDRs after a migration? http://msexchangeteam.com/archive/2004/07/21/189966.aspx I added X500 address with old server name as shown in the email propertiesfor a couple ofusers to test. Outlook then recognizes these user names on reply, but theemail still fails with NDR. It appears Exchange is still trying to deliver to the old server name instead of matching user name to the new server. There must be another setting required to make the user name on old server namematch touser name onnewservername?I found where someone said the migration mergeprogram maybe created a second X400 address along with X500for the old server? I tried this, but not sure I did it right. Mail replystill failed NDR. The old server is off line and will not be used. Any help or suggestions appreciated. Tommy

Did you reconfigure the outlook profiles and 'check name' back to the new server only? Also, what does message tracking say?

Thanks for the reply. Yes, the SBS old server is off-line as it conflicts with the new SBSserver. The new server is same domain and same IPnumber, just the server name is different. The old server PRIMENTSVR does not exist on the network now. The new server name is PRIME-SBS. All new emails work normally. Here is the X500 address from oneemail before upgrade.I added the X500 address below to the users address list on the new Exchange 2003 server PRIME-SBS. /O=PRIME/OU=PRIMENTSVR/CN=RECIPIENTS/CN=PKRUGMAN In Outlook on reply to this user, the check names responds with no error after I added the X500 address for the old server. When you put the cursor on the name, the outlook icon pops up next to the name. If you look at the user name properties, all you see is the X500 string above. Here is the NDR: Your message did not reach some or all of the intended recipients. Subject:RE: PTS05041, Stock quantity. Sent:12/5/2007 12:12 AM The following recipient(s) could not be reached: 'Paul Krugman' on 12/5/2007 12:12 AM The message could not be delivered because the recipient's destination email system is unknown or invalid. Please check the address and try again, or contact your system administrator to verify connectivity to the email system of the recipient. <prime-ems.com #5.1.2> I believe new Exchange 2003 server is still trying to sent the email to the old PRIMENTSVR, which it was never connected to or knows about. Suggestions?

Are you running cached mode? Could it be that your users still have an OAB from the old server? Also, does mail NDR if OWA is used?

This problem HAS TO BE (99.9999999% sure) lthe legacyExchangeDN. I know this may sound silly, but did you add the Custom X500 address Exactly like your example, with the Caps on the O= and such? They should be lower case I think. I remember an old tool used to import and make things uppercase, and you would have to go and make it lower case again. So your Example /O=PRIME/OU=PRIMENTSVR/CN=RECIPIENTS/CN=PKRUGMAN would need to be: /o=PRIME/ou=PRIMENTSVR/cn=RECIPIENTS/cn=PKRUGMAN I think I am pulling this one out of "Long Long ago" land.

Thanks John, that worked.I had tried all lower case, partial mixed case, and all upper case.

All, I'm facing similar issue after migrating a user from one Org to another. I have tried everything mentioned here except the last step of changing X500 format. When the user is replying to old emails, he is getting NDR: 5.1.2 His legacy DN of source server is already added as X500. he gets same NDR from OWA also. The X500 netry is in mixed case. But thats how it for all migrated users and only this user gets NDR. Anything else that I can try.

Hi,When you add custom x500 address in email addresses make sure you use small "x" later, Do not use X500 (X in Caps)Means use x500 not X500