We are trying to shutdown our last exchange 5.5 server and keep encoutering a delivery problem. Our enviroment has two routing groups A and B. In routing group B the last 5.5 server has been removed and it seems to work fine. All exeternal email is currently sent and recieved using the IMS on the 5.5 server in group A. Each time we attempt to remove this IMS and switch the incoming and outgoing mail to the 2000 server in this group all mail for users who’s mailboxes are on the 2000 server in group A can not recieve email from internal or external users. All mailboxes in routing group B have no problem sending messages to and getting message from the internet and can also get messages from mailboxes in routing group A.
I have used message tracking to try to determine the problem and it seems that message that are sent from routing group B when the arrive at the exchnage server in routing group A are trying to be routed to the internet insted of delivered locally. The user in routing group B will get and NDR with failed to relay error. Has anyone encountered this problem? I have checked all the settings and can not find anything that is not set correctly. Any help would be appreciated.