Почему Gmail помечается как спам на моем сервере postfix?

Я пытаюсь отправить письмо с постфикса различным провайдерам: Hotmail OK, Yahoo Не тестировался, Italian Provider OK, GMAIL KO!

У меня SPF и rDNS установлены правильно... это заголовок:

Delivered-To: mymail@gmail.com
Received: by 10.182.122.34 with SMTP id lp2csp107348obb;
        Thu, 16 Aug 2012 10:28:50 -0700 (PDT)
Received: by 10.216.198.145 with SMTP id v17mr1084539wen.1.1345138129729;
        Thu, 16 Aug 2012 10:28:49 -0700 (PDT)
Return-Path: <sender@mydomain.it>
Received: from ispconfig.myserver.it (ispconfig.myserver.it. [*.*.*.*])
        by mx.google.com with ESMTP id a27si7050105wej.31.2012.08.16.10.28.48;
        Thu, 16 Aug 2012 10:28:49 -0700 (PDT)
Received-SPF: pass (google.com: domain of sender@mydomain.it designates *.*.*.* as permitted sender) client-ip=*.*.*.*;
Authentication-Results: mx.google.com; spf=pass (google.com: domain of sender@mydomain.it designates *.*.*.* as permitted sender) smtp.mail=sender@mydomain.it
Received: from localhost (localhost [127.0.0.1])
    by ispconfig.myserver.it (Postfix) with ESMTP id 6A92076716
    for <mymail@gmail.com>; Thu, 16 Aug 2012 19:28:48 +0200 (CEST)
To: =?utf-8?B?U2VyZ2lvIEJlbGxpbmk=?= <mymail@gmail.com>
Subject: =?utf-8?B?TXVyYWxlc3RvcmUuaXQgLSBDb25mZXJtYSBsJ2FjY291bnQgU2VyZ2lvIEJlbGxpbmk=?=
From: Label <sender@mydomain.it>
Reply-To: Label <sender@mydomain.it>
Date: Thu, 16 Aug 2012 17:28:48 +0000
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline
MIME-Version: 1.0