Exchange Online - primary SMTP does not update?

[jbostoen]

 

Exchange Online doesn't seem to update the primary SMTP address, in contract to admin.office.com (portal).

I'm using AADConnect. In the AD, I used SMTP:newaddress@domain.onmicrosoft.com in the ProxyAddresses attribute.

The mail address gets added, but doesn't become primary. Even completely removing the 'stuck' address from ProxyAddresses, doesn't change anything. A

What am I missing, or is it just a matter of a lot of hours of patience? Or a trick to trigger the change?

Also, when do removed SMTP addresses (from proxyAddresses) get removed from Exchange Online as well?

[#2 · Accepted solution]

Generally speaking, you shouldn't be managing @onmicrosoft.com addresses from on-premises. For the scenario at hand, you can "override" the sync using the following cmdlet:

Set-Mailbox user@domain.com -WindowsEmailAddress user@domain.onmicrosoft.com

This will set user@domain.onmicrosoft.com as the primary SMTP, regardless whether the user is synced or not.

[#3]

Thanks. I actually just followed the logic for non-onmicrosoft.com addresses; what's the explanation for this situation where it shouldn't be accomplished with editing proxyAddresses when using AADConnect (hybrid situation)?

Also, how to remove the addresses still present in Exchange Online but NOT in AD on-prem? Deleting them through the ECP is impossible 'since they are synced'.

[#4]

You cant remove them, unless you stop DirSync. Or delete/recrate the object :)

[#5]

Thanks, the primary SMTP issue is solved. But I'm curious about "why" though. It doesn't seem to make a lot of sense, compared to managing proxyAddresses in the on-prem Active Directory.