Why is my mailbox still in the Queued state after n minutes?
In the great majority of cases, your migration will start within minutes after being submitted. Your mailbox will quickly advance from the Submitted state to the Queued state, and then to the Authenticating state.
In some exceptional situations, a mailbox may take longer to start (20 minutes or more). This may happen if we experience extremely high load where, for example, a single customer submits 100,000 mailboxes for migration.