Undelivered Mail Returned to Sender

[MAILER-DAEMON@xxxxxxxxxxxxxxxxxxxxxxx (Mail Delivery System)]

This is the Postfix program at host smtp-out-02.comm2000.it.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to <postmaster>

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                        The Postfix program

<rkozteimphye@xxxxxxxxxxx>: host smtp.naes.it[89.186.73.98] said: 554 Mail
    blocked by ASSP antispam service - a report will be sent to recipients (in
    reply to end of DATA command)

Reporting-MTA: dns; smtp-out-02.comm2000.it
X-Postfix-Queue-ID: EAEDA73918
X-Postfix-Sender: rfc822; kernprof@oss.sgi.com
Arrival-Date: Sun, 20 Apr 2008 09:58:07 +0200 (CEST)

Final-Recipient: rfc822; rkozteimphye@gambetti.it
Action: failed
Status: 5.0.0
Diagnostic-Code: X-Postfix; host smtp.naes.it[89.186.73.98] said: 554 Mail
    blocked by ASSP antispam service - a report will be sent to recipients (in
    reply to end of DATA command)
> --- Begin Message ---
>
> --- End Message ---