We are having issues with people receiving email addressed to someone else. Specifically, the "To" recipient and their email storage have both been removed from our Active Directory. Is there a way to prevent this?
Assuming the recipient's Active Directory account and Exchange mailbox have both been deleted, it seems like you have users receiving mail for legacy users whose accounts and mailboxes have been deleted. The Simple Mail Transfer Protocol (SMTP) addresses on those de-provisioned mailboxes have been deleted and were then added as secondary proxy addresses so that messages don't get bounced. In order to prevent these mailboxes from receiving messages addressed to those legacy users, remove the secondary proxy addresses.
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