We are about to migrate from IPSwitch to Exchange 2010. I have set everyone up in Exchange. We were hoping to migrate people department by department rather than trying to do 170 users all at once. Sending emails out from exchange to the outside world and receiving in from the outside world, works fine.
This issue we are having is trying to send from internal users on Exchange to internal users who are not yet using it. Those who are not using Exchange yet, do not receive the emails on the old email system.
I have tried disabling the non Exchange user's mailboxes, but then we get errors that the user doesn't exist and they still don't get the emails.
Exchange is simply trying to email within itself for internal users. I need to know if anyone knows of a way to make exchange email to a separate non-Exchange internal email system.