PHPMailer - correios indo direto para spam

Sempre que eu envio um e-mail automático usando o PHPMailer, ele vai direto para a pasta de spam no Gmail. Eu tentei encontrar uma solução para isso, mas eu não sei o suficiente sobre e-mails e cabeçalhos de e-mail.

Alguém pode explicar por que isso está acontecendo?

Código PHP está abaixo, seguido pelos cabeçalhos que aparecem no receptor.

Obrigado!

$mail = new PHPMailer;
$mail->From = "[email protected]";
$mail->FromName = 'Xenon Group Academy';
$mail->AddAddress($email);
$mail->Subject = "Your Xenon Group Academy login details";
$mail->IsHTML(true);
$mail->Body = "<html><body><h3>Welcome to the Xenon Group Academy</h3><p>The Academy is an online system that will allow you to access course materials, manage your assignments and network with other Xenon Group students.</p>
<p>To access your account, go to <a href='http://www.xenonacademy.org.uk'>www.xenonacademy.org.uk</a> and use the following details to login.</p><p><pre>E-mail:            $email</pre></p><p><pre>Password:       " . mysqli_real_escape_string($conn, $_POST['password']) . "</pre></p><br /><br /><p>Once you have logged in, we would recommend changing your password to something secure and easy to remember. You can also change your login e-mail address if you need to.</p><p>Welcome to the Academy, and good luck with your qualification!</p></body></html>";
$mail->Send();



Delivered-To: [email protected]
Received: by 10.49.109.71 with SMTP id hq7csp68808qeb;
        Thu, 23 May 2013 07:27:28 -0700 (PDT)
X-Received: by 10.180.37.243 with SMTP id b19mr25275110wik.12.1369319247650;
        Thu, 23 May 2013 07:27:27 -0700 (PDT)
Return-Path: <[email protected]>
Received: from server.xenonacademy.org.uk (vps69719724.123-vps.co.uk. [46.32.233.107])
        by mx.google.com with ESMTPS id n5si14506537wic.103.2013.05.23.07.27.26
        for <[email protected]>
        (version=TLSv1 cipher=RC4-SHA bits=128/128);
        Thu, 23 May 2013 07:27:27 -0700 (PDT)
Received-SPF: neutral (google.com: 46.32.233.107 is neither permitted nor denied by best guess record for domain of [email protected]) client-ip=46.32.233.107;
Authentication-Results: mx.google.com;
       spf=neutral (google.com: 46.32.233.107 is neither permitted nor denied by best guess record for domain of [email protected]) [email protected]
Received: by server.xenonacademy.org.uk (Postfix, from userid 10000)
    id DFBAAE0288; Thu, 23 May 2013 15:27:24 +0100 (BST)
To: [email protected]
Subject: Your Xenon Group Academy login details
X-PHP-Originating-Script: 10000:class.phpmailer.php
Date: Thu, 23 May 2013 15:27:24 +0100
From: Xenon Group Academy <[email protected]>
Message-ID: <[email protected]>
X-Priority: 3
X-Mailer: PHPMailer 5.2.6 (https://github.com/PHPMailer/PHPMailer/)
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/html; charset=iso-8859-1

<html><body><h3>Welcome to the Xenon Group Academy</h3><p>The Academy is an online system that will allow you to access course materials, manage your assignments and network with other Xenon Group students.</p>
<p>To access your account, go to <a href='http://www.xenonacademy.org.uk'>www.xenonacademy.org.uk</a> and use the following details to login.</p><p><pre>E-mail:            [email protected]</pre></p><p><pre>Password:     xxxxxxxx</pre></p><br /><br /><p>Once you have logged in, we would recommend changing your password to something secure and easy to remember. You can also change your login e-mail address if you need to.</p><p>Welcome to the Academy, and good luck with your qualification!</p></body></html>

Obrigado!

questionAnswers(3)

yourAnswerToTheQuestion