发送的注册电子邮件被归类为垃圾邮件

Question

registration email sent from a new website I am building end up in the receivers' spam folders, they are classified as spam. So far I have no idea why this happens. Therefore I am posting the email header of such a registration email. Please note that this email posted here has not been classified as spam, however all registration emails generated and sent are like this one.

Return-Path: c...t@l...friends.net
Received: from relay02.alfahosting-server.de ([109.237.142.238]) by
 mx-ha.gmx.net (mxgmx008) with ESMTP (Nemesis) id 0LkCb4-1U3Xb718IM-00cB3P for
 <hamstino007990@gmx.de>; Thu, 23 May 2013 23:44:03 +0200
Received: by relay02.alfahosting-server.de (Postfix, from userid 1001)
    id CBFAD32C008C; Thu, 23 May 2013 23:44:02 +0200 (CEST)
X-Spam-DCC: : 
X-Spam-Level: 
X-Spam-Status: No, score=-0.2 required=7.0 tests=BAYES_40,HTML_MESSAGE
    autolearn=disabled version=3.2.5
Received: from alfa3060.alfahosting-server.de (alfa3060.alfahosting-server.de [109.237.138.46])
    by relay02.alfahosting-server.de (Postfix) with ESMTP id 9EF9232C00C6
    for <hamstino007990@gmx.de>; Thu, 23 May 2013 23:44:00 +0200 (CEST)
Received: by alfa3060.alfahosting-server.de (Postfix, from userid 2905)
    id 9DDB32FFBE6B; Thu, 23 May 2013 23:44:00 +0200 (CEST)
To: hamstino007990@gmx.de
Subject: =?utf-8?Q?Willkommen_bei_LanguageFriends.net!?=
X-PHP-Script: staging.languagefriends.net/index.php for 77.58.5.166
User-Agent: CodeIgniter
Date: Thu, 23 May 2013 23:44:00 +0200
From: "L...Friends.net" <c...t@L...Friends.net>
Reply-To: "L...Friends.net" <c...t@L...Friends.net>
X-Sender: c...t@L...Friends.net
X-Mailer: CodeIgniter
X-Priority: 3 (Normal)
Message-ID: <519e8da0993a5@L...Friends.net>
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="B_ALT_519e8da0993ea"
X-Virus-Status: No
X-Virus-Checker-Version: clamassassin 1.2.4 with ClamAV 0.97.3/17264/Thu May 23 18:12:25 2013
Envelope-To: <hamstino007990@gmx.de>
X-GMX-Antispam: 0 (Mail was not recognized as spam); Detail=V3;
X-GMX-Antivirus: 0 (no virus found)

Thanks very much for any support.

Regards Sebastian

Answer 1

Do you have a proper SPF record set up for your domain? Most domains should respect whatever address your mail is coming from as long as it is in your SPF record. Wikipedia has a pretty good write-up on how SPF works.