php - 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/class.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

Answer

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