Starting this week, what should be the primary e-mail address, disappeared for some users. It seems to be related to name changes--and not just recent ones. Before this week, there have been no issues with name changes.
For example, SaraSmith@domain had a name change to SaraJones@domain. All was good until this week. Now, the e-mail addess SaraJones@domain is missing and her primay e-mail address has become SaraSmith@domain.
We are a hybid shop. Our AD is on-prem. Seems like e-mail address policy issue, right? I checked that and that's fine. Sync issue? Nope. On the AD side, SaraJones@domain is still SaraJones@domain. So our AD side is fine.
I can remove one of their e-mail aliases from proxyAddresses and, after re-sync, the primay e-mail address in EOL is SaraJones@domain. So that fixes the issue.
One thing I noticed is that I hadn't been changing the targetAddress when doing name changes. So Sara Jones' targetAddress would sill be firstname.lastname@example.org. I can change that to email@example.com, re-sync, and that solves the problem as well.
Just doing re-sync without making changes does not fix the problem. Even though AD has SaraJones@domain as the pimary e-mail addes, the EOL side still has SaraSmith@domain as the primay and SaraJones@domain doesn't even exist.
To me it seems to be a synchronization problem since Office 365 is not going to make any changes in your AD...could it happen that those objects were not well prepared in regards of UPN, MailAddress and ProxyAddresses attributes?
The accounts had been working fine prior to last week. The only attribute that I see that could potentially cause a problem is the targetAddress (the remote routing address thing). My process to change names did not change that attribute to reflect the new username. Weird.