We are finishing up a staged migration from Exchange 2003. All regular users have been migrated, but we are cleaning up a few shared mailboxes before the MX records can be updated to the Office 365 settings. We are using directory sync with and AD FS server.
The issue is that on one user (my user, which happens to be the one that setup Office 365, not sure if that's relevant) lost the *** Email address is removed for privacy *** proxyaddress in the cloud. Without that address, all external email gets bounced. From what I can tell, this shouldn't be possible in a dirsync setup. I'm not aware of any config changes. I have confirmed that the targetaddress attribute on premise did not change.
Can that address be added back? How was it removed?
The temporary solution I have for now was to create a new cloud user, update the target address to the new user, then create a mailflow rule to redirect email to my original synced user. This is not ideal because it is using 2 licenses for 1 user.
I have already tried adding a new proxy addresses on premise, but it seems onmicrosoft.com addresses aren't synced. I also tried adding a new address on the web portal and through powershell, but no luck with directory sync enabled.