We are trying to move users off Exchange 2007. Following various guides online, we've changed our Accepted Domain to be "internal relay" and created a "Send connector" to relay unhandled email for our domain to an external smart-host.
We then disabled the Mailbox for one Exchange user. The AD user is kept, just the Mailbox disabled (which says it removes mail-user attributes from the AD user).
Several people in the office are using OS X Mail (Snow Leopard with Exchange integration). When sending new email from that client, all works as expected. The email is forwarded to the external smart-host and lands in my Inbox outside exchange.
But for people who are using Outlook clients, sending new email to my account results in a "Delivery has failed to these recipients or distribution lists" message. The error is:
IMCEAEX-_O=FIRST+20ORGANIZATION_OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+ 28FKODFHF45SPDLT+29_CN=RECIPIENTS_CNfirstname.lastname@example.org #550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found ##
My guess is that Outlook is caching a direct reference to the deleted user in the address book or elsewhere, causing routing to be ignored. Does that sound right? If so, is there a way to force Outlook to update itself? If not, any other ideas?
Or maybe the issue is that Outlook references the remaining AD user account even though there is no more mailbox?
Edit: A bit more information. When I look in the Message Tracker I see that:
Email sent from Outlook clients to the disabled Exchange mailbox have a recipient of: IMCEAEX-_O=FIRST+20ORGANIZATION_OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+20+ 28FKODFHF45SPDLT+29_CN=RECIPIENTS_CNemail@example.com
Email sent from Outlook clients to normal Exchange mailboxes are just 'firstname.lastname@example.org'
Email sent from OS X Mail clients to either enabled or disabled mailboxes have normal recipients like 'email@example.com'.