When using a distribution list in Exchange 2010 we reveive a "Delivery has failed to these receipients or groups" eror. Each user in the Staff group is shown with en error below their email address that reads: "The recipient's e-mail system isn't accepting messages now. Please try resending this message later or contact the recipient directly."
To duplicate the problem, I set up an appointment in Exchange 2010 Calendar using Outlook 2007. I added the staff group as required. I UNchecked "Require a response". When I press Send, I immesiately get an Undeliverable return message.
At the top it says : Delivery has failed to these recipients or groups:
It then lists each staff by email address, and underneath each email address it reads: The recipient's e-mail system isn't accepting messages now. Please try resending this message later or contact the recipient directly.
This happened after the migration from Exchange 2007 to Exchange 2010. Nothing has changed with the exception of the domain controller which is still publisihing the same DN, but The server IP and Name (of course) is different. DNS has remained the same... GHowever, the issue was still happening before running dcpromo on the old DC to demote it...