need to migrate a single mailbox from 365 to exchange

Question

we are in hybrid mode, users in 365 cloud, exchange 2013 onsite, relay emails from 2013 to 365 for copiers and couple of programs.
one program is our helpdesk software, we migrated is mailbox to 365, but have not been able to get it to work with 365.

how can I migrate that single mailbox back to our local exchange server, so our helpdesk software will work tomorrow?

Answer 1

First confirm the mailbox has an Exchange GUID
From ON PREM Exchange powershell:

Get-RemoteMailbox <alias of cloud mailbox to move> | Format-List ExchangeGUID  

If it does not, fix per this article:
https://learn.microsoft.com/en-us/exchange/troubleshoot/move-mailboxes/migrationpermanentexception-when-moving-mailboxes

Then offboard per this article:
https://learn.microsoft.com/en-us/exchange/hybrid-deployment/move-mailboxes#move-exchange-online-mailboxes-to-the-on-premises-organization

or use Exchange Online PS:

https://thomasverwer.com/2015/07/07/offboarding-mailboxes-back-to-on-premises-exchange-with-office-365/

$opcred = get-credential domain\domainadmin  
Get-Mailbox -Identity username@contoso.com | New-MoveRequest -OutBound -RemoteTargetDatabase ‘Database01’ -RemoteHostName ‘hybrid.contoso.com’ -   
RemoteCredential $opcred -TargetDeliveryDomain ‘contoso.com’

Answer 2

I ran the powershell on my exchange server, and it does return and exchange GUID for the email account in question.

so I think I am running into issue when entering Target Delivery Domain, if I enter the FQND of my email server, say exchange@mydomain.com, the move fails with
Error: MigrationPermanentException: The target mailbox doesn‎'t have an SMTP proxy matching ‎'exchange.mydomain.com‎'. --> The target mailbox doesn‎'t have an SMTP proxy matching ‎'exchange.mydomain.com'.​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

if it is not the FQDN of the exchange server, what SHOULD the target delivery domain be?

Answer 3

target domain was it!
thanks!