I am beginning a migration to O365 from exchange 2010 and was checking the health of mailboxes prior to deploying the hybrid configuration.
I discovered a user's mailbox that had corruption and to cut he story short, I had to delete the mailbox and re-create it (leaving the AD user account intact)
All went well but now I have discovered that internal users get an NDR stating that the user cannot be found.
I have tried:
- to force an update on the OAB then forced outlook on another user's machine to download the OAB,
- removed the entry from the other users NK2 files,
It work fine when I use OWA to send mail to the new mailbox which leads to believe that there's a problem with distribution of the OAB.
Anyone assist me with this?