We are in the final phase of our migration from Exchagne 2003 to Exchange 2010 and have run into one issue that we cannot figure out.
Everything works fine whenever we shut down the Exchange 2003 server or remove the connector between the servers except for when users attempt to send email to a distribution list that was migrated from Exchange 2003. When these messages are sent they are never delivered and either sit in the Exchange 2010 retry queue (if we left the connector intact and shut down the Exchange 2003 server) or they hang in the Exchange 2003 server's "Messages with unreachable destinations" queue. In either case, the messages will be delivered when the Exchange 2003 server is back on and the connector is created between Exchange 2003 and Exchange 2010.
I have been unable to find any descriptions of this particular problem on Technet. Please let me know if anyone knows what is causing this and how to fix it as this is the only issue keeping us from getting rid of our Exchange 2003 server.
Thanks...Ray