The mailbox fail to sync with the following error in the log file:
M61 Error Quest.MigrationManager.Exchange.Basis.LdapHelperException: Can't find object by LEDN - '
Run the following query to see the mailbox ID and also the information from the mailbox:
select * from MAILBOX_PROCESSING_PROPERTY
update MAILBOX_PROCESSING_PROPERTY set PROP_VALUE = '