I am in the middle onf an Exchange 2003 to 2007 upgrade and have moved the Services like SMTP, OWA etc to the new server.
I have moved a couple of mailboxes accross and now when emails are sent to those email addresses with mailboxes on the new server the sender gets a undeliverable messsage:
#5.1.1 SMTP; 550 Address unknown> #SMTP#
Those users on the old server can received mail?
Please can you help.