Emails not able to copy from backup using zmmailbox

[sibin]

Hello,

Our old server on which Zimbra was running has crashed and we have setup the zimbra on another server. We are now trying to copy the emails from the backup server to an email account using the zimbra cli command 'zmmailbox' but it throwing the below error.

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ERROR: zclient.CLIENT_ERROR (/opt/zimbra/store/0/Recovered-mails/store/0/11/msg/0/2854-13347.msg does not contain a valid RFC 822 message)
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I have tried moving out that particular mail '2854-13347.msg' out of this directory but it is showing the same error for another mail.

Please let me know any workaround on this as old emails are very much critical for my business.

Thanks