The remote server returned an error: (401)
After you apply this hotfix to the Unified Access Gateway server, you must add the following InconsistentCookieThreshold DWORD value:
DWORD name: InconsistentCookieThreshold
DWORD value: 30 (Decimal)
Note For especially large mailboxes, you may have to increase the DWORD value.
Important You should remove this registry subkey from the Unified Access Gateway server after you complete the mailbox migration task.
After you apply this registry subkey you must enable the Unified Access Gateway server configuration and then perform an Internet Information Services (IIS) reset.