One of our exchange users (2007/2010) is randomly having problems recieving email. When several people have replied to her (they are in the same Exchange organization) they get an NDR of 5.1.3 which means 'invalid recipient'. Delivery has failed to these recipients or distribution lists: 'firstname lastname <firstname.lastname@domain.com' I can see that this email isn't completely valid as it is missing an '>' at th end. However, I can't see how this error occurs as users are replying to an existing email.

Hi, This can occur if the user's LegacyExchangeDN attribute has been changed since he last sent that email which is being replied to. In this case other users have NDRs for replying to the email of the problematic user. They dont have problem in sending new mails to that user though. Regards, Laeeq Qazi|Team Lead(Exchange + Sharepoint + BES + DynamicsCRM) www.HostingController.com

I'm not so sure of that. Usually a change to the legacyExchangeDN causes consistent, not intermittent, bounces and they have a converted X.500-type address, not an SMTP address.-- Ed Crowley MVP"There are seldom good technological solutions to behavioral problems.". "Laeeq Qazi" wrote in message news:4d91dbea-f1ae-48f4-a1d9-62f34424077e...Hi, This can occur if the user's LegacyExchangeDN attribute has been changed since he last sent that email which is being replied to. In this case other users have NDRs for replying to the email of the problematic user. They dont have problem in sending new mails to that user though. Regards, Laeeq Qazi|Team Lead(Exchange + Sharepoint + BES + DynamicsCRM) www.HostingController.com Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

On Thu, 11 Mar 2010 21:55:43 +0000, sgrigg wrote:>One of our exchange users (2007/2010) is randomly having problems recieving email. When several people have replied to her (they are in the same Exchange organization) they get an NDR of 5.1.3 which means 'invalid recipient'. Delivery has failed to these recipients or distribution lists: 'firstname lastname <firstname.lastname@domain.com' I can see that this email isn't completely valid as it is missing an '>' at th end. However, I can't see how this error occurs as users are replying to an existing email. Users do some pretty weird things. You should verify that they aren'tdoing more than just replying. Check their contacts to see if theyhave an contact for the person and if that contact has a valid e-mailaddress. Usually, problems with incomplete addresses, addresses withapostrophes at one end or the other, or at both ends, etc. are usererrors and Contacts are a good number of those.---Rich MatheisenMCSE+I, Exchange MVP--- Rich Matheisen MCSE+I, Exchange MVP

Hi, I agree with Rich. Please check if the receiver is in sender's contact list and the contact have a valid email address. I also suggest you use Adsiedit.msc to locate the problematic user. Check the attribution of "proxyaddress" and "Targetaddresses"(for contact). Here are some samples of bad addresses: User@.domain.com User.@domain.com User@ domain.com User@ domain.com User@%domain.com User@,domain.com Hope this helps. Thanks, Elvis

Hi, How things are going? Any update on the issue? If so, please let me know.