Unable to Migrate mailbox to Office 365 - Source Mailbox Already being Moved

When migrating a mailbox from on premises Exchange Server to Office 365, it failed with below error message.

Transient error SourceMailboxAlreadyBeingMovedTransientException has occurred. The system will retry (1/620).

Restarted the Microsoft Exchange Mailbox Replication service and resumed the mailbox move - the mailbox was moved successfully.