One user on Exchange 2007 gets NDR's, occasionally...seems to be when there's a 'Reply All' there is a failure to that address. User sees this (note that below address is missing ending ' > '): Delivery has failed to these recipients or distribution lists: John Glassman <John.Glassman@AmericanWell.com The format of the recipient's e-mail address isn't valid. A valid address looks like this: username@contoso.com. Microsoft Exchange will not try to redeliver this message for you. Please check the e-mail address and try sending the message again, or provide the following diagnostic text to your system administrator. _____ Sent by Microsoft Exchange Server 2007 Diagnostic information for administrators: Generating server: BOS-MAIL-01.contoso.com John Glassman <John.Glassman@contoso.com #550 5.1.3 STOREDRV.Submit; invalid recipient address #SMTP# Original message headers: Received: from BOS-MAIL-01.contoso.com ([x.x.x.120]) by bos-mail-01 ([x.x.x.120]) with mapi; Tue, 4 May 2010 17:33:26 -0400 MIME-Version: 1.0 Content-Type: text/plain Date: Tue, 4 May 2010 17:33:26 -0400 Message-ID: <CA9974D56BCABD44BD037E851C1C25610162C2C462@bos-mail-01> Subject: RE: Image request Excerpt from logs of the most recent message: 2010-05-04T21:33:26.859Z,,,,BOS-MAIL-01,Failure,,DSN,DSN,580955,<fbb85ae6-6192-4d11-b3f1-c987d77a9fd3>,John.Glassman@contoso.com,,4774,1,,,Undeliverable: RE: Image request,MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@contoso.com,<>, 2010-05-04T21:33:26.871Z,x.x.x.120,BOS-MAIL-01.contoso.com,x.x.x.120,BOS-MAIL-01,,,STOREDRIVER,RECEIVE,580956,<CA9974D56BCABD44BD037E851C1C25610162C2C462@bos-mail-01>,JGoldman@external.com;Tom.Sawyer@contoso.com;DistroList@external.com,,17234,3,,,RE: Image request,John.Glassman@contoso.com,John.Glassman@contoso.com,04I: 2010-05-04T21:33:26.937Z,,,,BOS-MAIL-01,ContentConversion,,ROUTING,TRANSFER,580957,<CA9974D56BCABD44BD037E851C1C25610162C2C462@bos-mail-01>,DistroList@external.com;JGoldman@external.com,,14548,2,,580956,RE: Image request,John.Glassman@contoso.com,John.Glassman@contoso.com, 2010-05-04T21:33:26.951Z,,BOS-MAIL-01,,bos-mail-01,,,STOREDRIVER,DELIVER,580955,<fbb85ae6-6192-4d11-b3f1-c987d77a9fd3>,John.Glassman@contoso.com,,4947,1,,,Undeliverable: RE: Image request,MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@contoso.com,<>, 2010-05-04T21:33:27.016Z,,BOS-MAIL-01,,bos-mail-01,,,STOREDRIVER,DELIVER,580956,<CA9974D56BCABD44BD037E851C1C25610162C2C462@bos-mail-01>,Tom.Sawyer@contoso.com,,17360,1,,,RE: Image request,John.Glassman@contoso.com,John.Glassman@contoso.com,2010-05-04T21:33:26.830Z 2010-05-04T21:33:27.178Z,x.x.x.120,BOS-MAIL-01,x.x.x.220,bos-ex-01.contoso.com,08CC33F8B4130BFF,Intra-Organization SMTP Send Connector,SMTP,SEND,580957,<CA9974D56BCABD44BD037E851C1C25610162C2C462@bos-mail-01>,JGoldman@external.com;DistroList@external.com,250 2.1.5 JGoldman@external.com ;250 2.1.5 DistroList@external.com ,14548,2,,;,RE: Image request,John.Glassman@contoso.com,John.Glassman@contoso.com,2010-05-04T21:33:26.830Z WYSIWYG...YMMV

Could be a cached or incorrect entry in the senders contacts.

Thanks Andy, but this latest one is from the user in question doing a Reply All and getting a NDR for their own address...that's part of what makes this so puzzling.WYSIWYG...YMMV

When they choose Reply All, is their own email listed? Also make sure the OAB has downloaded to the client if they are in cache mode. Test with OWA as well and see if the problem persists.

Hi, For this issue, please first improve the Diagnostic Logging to Expert based on the below command: Get-EventLogLevel MSExchangeTransport | Set- EventLogLevel -Level Expert After that, please reproduce this issue and check the Event Log. If no value information is showed, please continue to run Get-TransportAgent |fl command to check for transport agent. Then post it here. Thanks Allen

I have not been able to revisit this, but have not seen any more NDR's either. I'm thinking it was a corrupt/incorrect entry in someone's cache. The address was missing the trailing '>' in every NDR... Nothing more to see here folks....move along. WYSIWYG...YMMV