On-Prem Primary SMTP Address not in sync with O365 email address

Question

_{Tuesday, July 5, 2016 12:40 PM}

Hi All

I have a weird issue that I just cannot get my head around. I was hoping someone may be able to push me in the right direction.

We are running in a Hybrid Environment with two Exchange 2013 front ends being the Hybrid servers, and Exchange 2010 Sp3 UR11 as the backend servers where user's mailboxes are located. We have multiple sites accross different countries.

My issue in a nutshell is this :

On premise - a user's email address is stamped as follows based on their country :

alias@<COUNTRYCODE>.company.com

On-premise this works as expected and everything is fine and dandy. Users appear in the GAL with the correct Primary SMTP address, and looking at the proxyAddresses attribute on the AD account - everything is as expected :

SMTP:alias@<COUNTRYCODE>.company.com

Now...

On the Dirsync server - we are ( at the moment ) syncing to O365 based on OU. We also have most of the attributes selected to sync up there - including "proxyAddresses" and "mail" etc...

What I find is that for SOME sync'ed users in O365 ( not all of them ) - the PRIMARY SMTP address does not have the same value as the on-premise account. For the On Premise account - the PRIMARY SMTP address is correct, but for their sync'ed accounts ( which does NOT have mailboxes in O365 yet ) - their email addresses shows up as :

alias@<TENANTNAME>.onmicrosoft.com

We have one site that have ben Migrated fully to O365 - they have mailboxes in O365 and all their addresses seems to be correct. However - when one of these users try to send a mail to one of the users with an incorrect PRIMARY SMTP address they get a NDR - obviously because the recipient cannot be found due to the Onmicrosoft.com primary address.

I really hope this makes sense, and that someone is able to assist me. If not I'll have to log a call with MS.

Thanks in advance !

All replies (5)

_{Tuesday, July 5, 2016 7:26 PM ✅Answered}

Do you have the <COUNTRYCODE>.company.com domain verified in O365 and configured as Accepted domain for Exchange Online?

_{Tuesday, July 5, 2016 7:27 PM | 1 vote}

You can always "override" the sync process by using the following cmdlet:

Set-Mailbox [email protected] -WindowsEmailAddress [email protected]

This cmdlets will add [email protected] as the primary SMTP, while preserving the old one as secondary. It will bypass any DirSync restrictions, so you can use it with synced users as well.

_{Wednesday, July 6, 2016 6:00 AM}

Hi Vasil

Thanks for the reply, but remember - these are just Dirsync'ed users - they do not have mailboxes in O365 yet, so :

1. No need to verify the user@<country>.domain.com domain YET ( AFAIK )

2. Like I said - their On-Premise email addresses are correct. The problem i have is that if someone from that site that have mailboxes in O365 tries to email an on-premise user - the email address for the on-premise guys appear to these people as user@<tenant>.onmicrosoft.com, which is not correct. What makes it even more confusing is that it's not the case for ALL on-premise accounts - there are some that shows up correctly with the correct primary SMTP address

This leads me to believe that the primary SMTP address for some of the on-premise users are not syncing to O365 properly - even though Dirync is set to sync most on-premise user attributes which includes proxyAddresses and mail attributes...

Looks like I'm going to have to log a call with MS huh ?

_{Wednesday, July 13, 2016 2:18 PM}

Microsoft verified that I do indeed need to register and verify all my other domains in the on-premise environment in order for all the sync'ed accounts ( even those without mailboxes in the cloud ) to be correctly sync'ed and stamped with the correct primary SMTP addresss in O365...

Thanks All !

_{Thursday, March 15, 2018 8:13 PM}

You can always "override" the sync process by using the following cmdlet:

Set-Mailbox [email protected] -WindowsEmailAddress [email protected]

This cmdlets will add [email protected] as the primary SMTP, while preserving the old one as secondary. It will bypass any DirSync restrictions, so you can use it with synced users as well.

This is what did it for me!