ERROR: [275-24-52-8004011D] Unable to open mailbox for user 'User@Domain.com'
MAPI error 8004011D
Error: The attempt to log on to Microsoft Exchange has failed.
Component: Microsoft Exchange Information Store
Low level error: 0000096C
This may be caused by Cached Mode being checked in the Outlook Profile for the migration administrator account.
In Outlook select File | Account Settings | Account Settings | Change
then uncheck 'Use Cached Exchange Mode'
Click Next, OK, Finish and Close
remember to restart Outlook for changes to take effect.
When a New Profile is created by default Cached Mode is checked. So if you recreate the profile or create a new one you will need to uncheck this setting.