Today I was working with a client who has completed a pilot project for Office 365. The Admin was working on prepping to move all mailboxes to the cloud when he came upon a problem. The company had just hired a new employee, and instead of creating the user’s mailbox in the on-premises Exchange 2007 Organization he decided to create it in Exchange Online. The Active Directory account had already been created, so he went to the Exchange Management Console (EMC), selected the On-Premises Organization, right mouse clicked on the Recipient Container and selected "New Remote Mailbox". Problem with this is that you cannot create a Remote Mailbox for an existing user using the EMC; you only have the option of creating a new user and the mailbox. Ok, easy enough, if the EMC can’t do it I’m sure you can do it via the Exchange Management Shell (EMS). Yep sure enough a quick search found this, http://technet.microsoft.com/en-us/library/ff625227.aspx. He went ahead and used the Enable-RemoteMailbox Command, as described in the TechNet site, problem #2, this returns an error that the Address is invalid for the Routing Address.
He contacted me and a quick Bing search found this, Steve Goodman’s Exchange Blog and the fix, http://www.stevieg.org/2012/05/enabling-a-remote-mailbox-on-office-365-fails/ Seems that Microsoft neglected to mention the need for the –RemoteRoutingAddress parameter when using the Enable-RemoteMailbox command. Thanks to Steve’s blog post the issue was quickly resolved.
From Steve’s Blog:
When enabling the remote mailbox, use the –RemoteRoutingAddress parameter, specifying your alias and service domain/Office 365 tenant, for example:
Enable-RemoteMailbox <username> -RemoteRoutingAddress <alias>@<tenantName>.mail.onmicrosoft.com