All mail leaving my server is getting marked as spam in gmail.

[rnawky]

All emails coming from my dedicated server are getting marked as spam in gmail. What could be the cause of this?

[servertechs]

Do you have RDNS setup for the mailserver Ip?

[rnawky]

Yes

PTR record for the servers IP address resolves to the hostname of the server and the A record for the hostname resolves to the same IP address.

[rnawky]

Here's an email header. From what I can tell, it's identical to what they were before this started to happen.

                                                                                                                                                                                                                                                               
Delivered-To: rnawky2@gmail.com
Received: by 10.220.77.82 with SMTP id f18cs256189vck;
        Sat, 27 Feb 2010 15:37:05 -0800 (PST)
Received: by 10.101.152.19 with SMTP id e19mr3383502ano.98.1267313825745;
        Sat, 27 Feb 2010 15:37:05 -0800 (PST)
Return-Path: <ACCOUNTNAME@zeus.ryankearney.com>
Received: from zeus.ryankearney.com (zeus.ryankearney.com [174.123.60.106])
        by mx.google.com with ESMTP id 2si4750232gxk.14.2010.02.27.15.37.05;
        Sat, 27 Feb 2010 15:37:05 -0800 (PST)
Received-SPF: pass (google.com: best guess record for domain of ACCOUNTNAME@zeus.ryankearney.com designates 174.123.60.106 as permitted sender) client-ip=174.123.60.106;
Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of ACCOUNTNAME@zeus.ryankearney.com designates 174.123.60.106 as permitted sender) smtp.mail=ACCOUNTNAME@zeus.ryankearney.com
Received: from ACCOUNTNAME by zeus.ryankearney.com with local (Exim 4.69)
	(envelope-from <ACCOUNTNAME@zeus.ryankearney.com>)
	id 1NlWDY-0006xz-Io
	for rnawky2@gmail.com; Sat, 27 Feb 2010 18:36:40 -0500
To: rnawky2@gmail.com
Subject: Email Subject
X-PHP-Script: www.DomainEmailedFrom.com/Script.php for 1.2.3.4
From: "Someone" <webmaster@DomainEmailedFrom.com>
Auto-Submitted: auto-generated
Message-ID: <20100227233646.586f92b7ae42@www.DomainEmailedFrom.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 8bit
X-Priority: 3
X-Mailer: vBulletin Mail via PHP
Date: Sat, 27 Feb 2010 18:36:46 -0500
X-AntiAbuse: This header was added to track abuse, please include it with any abuse report
X-AntiAbuse: Primary Hostname - zeus.ryankearney.com
X-AntiAbuse: Original Domain - gmail.com
X-AntiAbuse: Originator/Caller UID/GID - [532 529] / [47 12]
X-AntiAbuse: Sender Address Domain - zeus.ryankearney.com

Looking at the headers, I can't find any reason why Gmail would mark it as spam. Zeus.ryankearney.com is the hostname, 174.123.60.106 is the shared IP in cPanel.