Unable to move large mailboxes to O365 when TMGISAUAG is acting a a F/W between on-premise Exchange and Exchange Online.
Informational: The request has been temporarily postponed because the mailbox is locked, request will continue at xx:xx:xx
Add all of the IP ranges noted in the following:
Forefront TMG console -> Intrusion Prevention System -> Behavioural Intrusion Detection -> Configure Flood Mitigation Settings.
Apply Configuration Change, wait and then the move request will continue if it has failed resume or create a new request