Office 365 > Outlook
To reconfigure Outlook after the mailbox upgrade:
Note: If you have Outlook open during the migration you may be reach this screen, simply restart Outlook.
Enter your username and password
Outlook should now be reconfigured to sync with the new email server.
After you have been migrated to the new system launch Outlook and click "Allow" when you get this dialogue box.
Note: Outlook may ask you to verify your username and password.