Cannot find a recipient that has mailbox GUID <many numbers>The reason for this error is that the mailbox has been created in Office 365 and lacks the proper attributes in the On-Premises environment. So, connect to Office 365 using PowerShell and run the following command.
Get-Mailbox john.doe@domain | fl ExchangeGuidNext, verify that the remote mailbox On-Premises is lacking the proper attribute.
Get-RemoteMailbox john.doe@domain | fl ExchangeGuidYou'll notice that the On-Premises attribute are nothing but zeroes. Copy and paste the attribute from Office 365 on to you On-Premisies environment using the following command.
Get-RemoteMailbox john.doe@domain | Set-RemoteMailbox -ExchangeGuid <copied from Office 365>That's is. Moving the mailbox from Office 365 to you On-Premiese environment should now work just fine. Or will it? If your On-Premises environment is published by Forefront Threat Management Gateway (TMG) 2010 you might also stumble upon the following error in your move request logs.
Relinquishing job because the mailbox is lockedOr the following status of the request.
StalledDueToMailboxLockThis might by caused by server affinity of the published web farm or it could be as simple as flooding. If you're certain that affinity is working properly you'll have to do some work on your TMG server to fix the flooding issue. Check out the below link for detailed instructions of what to do.