This could start importing the info and begin logging the information during the /opt/zimbra/log/import.log file. You'll need to allow the zimbraMailboxMoveSkipBlobs attribute and disable zimbraMailboxMoveSkipHsmBlobs attribute within the supply(NG) server right before initiating the account migration. In such a case, you migrate your service with the aged server to the https://www.hostscheap.com/zimbra-migration-service