Forum Discussion
LegacyDN with EXO (Microsoft 365)
Hi all, suddenly out of nowhere one of the Outlook clients in an office is unable to send an email to a M365 native recipient of the same org which never was migrated from onprem Exchange as this ...
IMO, this warrants a support call as the legacyExchangeDN should not change. Unless something happened on the back-end. Make sure there is no IAM process that recreated the user/mailbox or another process that overwritten it; a (proper) restore w/reconnect (to mailbox) should not be a problem. And yes, behind the scenes, legacyExchangeDN is still used for internal resolution of recipients.