Cannot migrate to a Destination mailbox equal to the Source mailbox: The Source mailbox has the same email address as the Destination. In addition, the Source email system is the same as the Destination email system. To prevent accidental migration of a mailbox to self (and so the duplication of all content), MigrationWiz detect this condition and issues an error to prevent migration.
Ensure that the Source and Destination mailboxes are different, by editing connector or mailbox properties. Note that MigrationWiz supports scenarios where the Source and Destination mailboxes have the same email address. However, in this case, the Source and Destination systems can't be identical.