Office 365 Mailbox Migration – RemoteRoutingAddress Issues

I recently started an Office 365 Exchange migration batch job with several thousand mailboxes. The migration of the mailboxes was working just fine, but we heard reports of bounced messages to a few migrated mailboxes.

Remote Server returned ‘554 5.4.6 Too many hops’

After troubleshooting this problem for a few hours, I determined that the problem was with an incorrect setting of the RemoteRoutingAddress. Our Exchange 2013 Email Address Policy is pretty simple:

Email Address Policy

Primary: @contoso.com
Address 2: alias@contoso.mail.onmicrosoft.com

Address 2 was added to our policy when the Office365, Exchange Hybrid wizard was successfully run for the first time. Now my current problem is several migrated mailboxes had the wrong RemoteRoutingAddress.

For some reason, after migrating this mailbox to Exchange Online, the incorrect RemoteRoutingAddress was set on the mailbox. Simply selecting the correct address of:

alias@contoso.mail.onmicrosoft.com in the drop down list resolved the issue. Now I am curious, how many other mailboxes had the exact same problem, and why? I created the following powershell script to search all remote mailboxes for this same problem.

Get-RemoteMailbox -ResultSize Unlimited | Where-Object {$_.RemoteRoutingAddress -notlike “*.mail.onmicrosoft.com”}

This script will search all remote mailboxes that have this problem. Now the question is why is this happening? Since I don’t have the alias@contoso.onmicrosoft.com address in my email address policy, why does the mailbox migration add this smtp address and set it as the remoteroutingaddress? At this point I am not sure, but I am looking into it. If anyone knows why this is happening, or has a more permanent solution let us know. Thanks!

About Parker Jardine

Manager of Systems Administration in the Information Technology Higher Education space. I enjoy biking, climbing, hockey, camping, mountaineering, hunting, paragliding, and just being outdoors. You can read my Make Magazine project articles about a diy solar panel and solar systems design in volumes 12 and 14.

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3 Responses to Office 365 Mailbox Migration – RemoteRoutingAddress Issues

Dario says:

September 29, 2017 at 2:59 am

Having the same issue today, and i just stumbled into this link, exactly the same problem i have, i’m migrating users from Exchange 2010 to o365, and after the migration is done, Exchange is stamping a user@tenant.onmicrosoft.com as the on-premise remote mailbox routing address, instead of user@tenant.mail.onmicrosoft.com, did you find root cause ?

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Parker Jardine says:

September 29, 2017 at 8:26 pm

Dario,
I never did find the root cause of this issue. I did upgrade Exchange 2013 to CU15 and re-run the hybrid wizard. The issue only appeared during a mailbox migration , so I thought a newer version of Exchange On-premise would solve this issue. Luckily this is not a permanent issue, once all of your mailboxes have been migrated the issue becomes moot.

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David Bell says:

March 16, 2018 at 11:27 pm

I’m encountering this issue on every mailbox migration to 365 from our Exchange 2013 server. Not a single mailbox migration has automatically updated this setting.

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