PHPMailer with GMail: SMTP Error

I am making use of PHPMailer to send mail through GMail. The code I use is straight from a tutorial and it works perfectly on my laptop. However, testing this on a Windows 2003 Server - it seems to always return an SMPT error:

SMTP Error: Could not connect to SMTP host. Mailer Error: SMTP Error: Could not connect to SMTP host.

Here is the settings I use in PHPMailer:

include("phpmailer/cl开发者_运维技巧ass.phpmailer.php");
$mail = new PHPMailer();
$mail->IsSMTP();
$mail->SMTPAuth = true; // enable SMTP authentication
$mail->SMTPSecure = "ssl"; // use ssl
$mail->Host = "smtp.gmail.com"; // GMAIL's SMTP server
$mail->Port = 465; // SMTP port used by GMAIL server

Can I say with confidence that this isn't a port issue, since I am connecting to another server on port 465 and it is sending mail. If not, please explain.

How can I resolve this issue?

Thanks all for any help

First thing notice off-hand: Gmail uses TLS. Don't know if having SSL instead of TLS will make much of a difference but SSL is the predecessor to TLS.

I recommend checking out also, its phpmailer customized for using gmail. PHPGMailer

To use PHPMailer with gmail, don't use SSL/465 (it's been deprecated since 1998), use TLS/587 as Noctrine suggests, and here's how:

include 'phpmailer/class.phpmailer.php';
$mail = new PHPMailer;
$mail->IsSMTP();
$mail->SMTPAuth = true; // enable SMTP authentication
$mail->Host = "tls://smtp.gmail.com"; // GMAIL's SMTP server
$mail->Port = 587; // SMTP port used by GMAIL server
...

You should find that works.