I have created a distribution group and it will work ONLY under the following condition. When the outlook client selects the distribution group to send mail to, the group must first be expanded out (clicking on + to left of DG name) to show all the email addresses. We would like to be able to send without going through this step - seems petty, but it is irritating to users. If not expanded out, no email is sent. Thanks for the help.

What happens when it fails? What is the exact error client receive?

No errors at all - it just never reaches any recipient. Note: All are smtp mailboxes on outside (many different) domains. Although when the DG is expanded, all recipients receive the mail.

I would check message tracking and see what path the message takes when it fails. It may be failing during expansion. To that end, if you check the advanced tab of that DG, verify that the expansion server is valid if defined. If message tracking doesnt tell you anything, increase transport diags for the MSExchangeTransport and send some test messages to that DG:http://technet.microsoft.com/en-us/library/bb691172(EXCHG.80).aspx

Hi Tullyc, Please try Andy’s suggestions and let us know the result. Do the issue only happen in this distribution group or all distribution groups? You could raise transport log level by running the following command: Get-eventloglevel –id msexchangetr* | set-eventloglevel –level high Then you could check the event log when the issue occurs and see if it can give you some clues. Thanks, Elvis

Hi Tullyc,How things are going? Any update on the issue? If so, please let us know. Thanks,Elvis