Issue with Moving phpmailer Page from Localhost to Server - php

Question

I have been developing a page that will automatically send emails from a Gmail account to mail accounts of various origin for specific users of my site. I have this working perfectly on Localhost. The mails are received by the users and also deposited in the "Sent Items" of the Gmail account.
However, as soon as I migrate this to the server we are using it no longer works. The code is as follows :-
$mail = new PHPMailer();
try
{
$mail->CharSet = "UTF-8";
// telling the class to use SMTP
$mail->IsSMTP();
// enables SMTP debug information (for testing)
// 1 = errors and messages
// 2 = messages only
$mail->SMTPDebug = 0;
// enable SMTP authentication
$mail->SMTPAuth = true;
// sets the prefix to the servier
$mail->SMTPSecure = "tls";
// sets GMAIL as the SMTP server
$mail->Host = "smtp.gmail.com";
// set the SMTP port for the GMAIL server
$mail->Port = 587;
// GMAIL username
$mail->Username = "xxxxxxx#gmail.com";
// GMAIL password
$mail->Password = "P4ssw0rd";
//Set reply-to email this is your own email, not the gmail account
//used for sending emails
$mail->SetFrom($from);
$mail->FromName = "XXX";
$mail->AddReplyTo('xxxxxxx#gmail.com' , 'XXX');
// Mail Subject
$mail->Subject = $subject;
//Main message
$mail->MsgHTML($message);
$mail->AddAddress($to, "");
$mail->Send();
}
catch (phpmailerException $e)
{
echo $e->errorMessage(); //Pretty error messages from PHPMailer
}
catch (Exception $e)
{
echo $e->getMessage(); //Boring error messages from anything else!
}
Setting the Debug to 1 on localhost produces the expected errors if something goes wrong. However, nothing seems to happen on the Server. Please help.