Мне приходит письмо от Undelivered Mail Returned to Sender (текст ниже) что делать? как ето исправить?

This is the mail system at host s64-67.furanet.com.

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The mail system

: host mxs.mail.ru[94.100.176.20] said: 550 Message was not
accepted -- it contains invalid headers. More specially, 'From:' header
must match user you are sending mail from. See
http://help.mail.ru/mail-help/mailer/popsmtp for details. (in reply to end
of DATA command)

Reporting-MTA: dns; s64-67.furanet.com
X-Postfix-Queue-ID: A7F00499BC
X-Postfix-Sender: rfc822; Dgin43@mail.ru
Arrival-Date: Fri, 3 May 2013 21:36:14 +0200 (CEST)

Final-Recipient: rfc822; Dgin43@mail.ru
Action: failed
Status: 5.0.0
Remote-MTA: dns; mxs.mail.ru
Diagnostic-Code: smtp; 550 Message was not accepted -- it contains invalid
headers. More specially, 'From:' header must match user you are sending
mail from. See http://help.mail.ru/mail-help/mailer/popsmtp for details.