Verify Exchange server is accessible and migrate again
If the target Exchange environment is available, the error may have been caused by a temporary network or Exchange issue
Please verify that the target Exchange server is operational and accessible from the migration machine. You can do this by opening Outlook with the migration profile to confirm access. Logged in as your account with Admin Privaledges, try going to File | Open | Other User's Folder then access the target user you're trying to migrate, this should not fail.
To ensure that the Outlook MAPI is working correctly it is recommended to do one of the following: Re-create the Profile being used for the migration, run a "Repair" of the Outlook client or a "FIXMAPI" from the command line.
The Exchange profile must also be configured to prompt for credentials and NOT use Cached Exchange Mode. To do this:
1. Open the Mail icon from the Control Panel
2. Click Show Profiles.
3. Highlight the Exchange profile and click Properties.
4. Click Email Accounts.
5. Under the Email section, select "View or change existing e-mail accounts" and click Next.
6. Highlight Microsoft Exchange Server and click Change....
7. Under the Microsoft Exchange Server box, deselect "Use Cached Exchange Mode".
8. Click More Settings....
9. Select the Security tab.
10. Check the box for "Always prompt for user name and password."
11. Click OK, Next, and Finish saving the profile settings.
NOTE: The Exchange profile must also be configured to "Prompt for a profile to be used"