ช่วยดู ERROR SMTP Error: Could not authenticate ให้หน่อยครับ

<?php
	require_once('class.phpmailer.php');
	$mail = new PHPMailer();
	$mail->IsHTML(true);
	$mail->IsSMTP();
	$mail->SMTPAuth = true; // enable SMTP authentication
	$mail->SMTPSecure = "ssl"; // sets the prefix to the servier
	$mail->Host = "smtp.gmail.com"; // sets GMAIL as the SMTP server
	$mail->Port = 465; // set the SMTP port for the GMAIL server
	$mail->Username = "[email protected]"; // GMAIL username
	$mail->Password = "**************"; // GMAIL password
	$mail->From = "[email protected]"; // "[email protected]";
	//$mail->AddReplyTo = "[email protected]"; // Reply
	$mail->FromName = "Mr.Weerachai Nukitram";  // set from Name
	$mail->Subject = "Test sending mail."; 
	$mail->Body = "My Body & <b>My Description</b>";

	$mail->AddAddress("[email protected]"); // to Address


	//$mail->AddCC("[email protected]", "Mr.Member ShotDev"); //CC
	//$mail->AddBCC("[email protected]", "Mr.Member ShotDev"); //CC

	$mail->set('X-Priority', '1'); //Priority 1 = High, 3 = Normal, 5 = low

	if(!$mail->Send()) {
echo 'Message was not sent.';
echo 'Mailer error: ' . $mail->ErrorInfo;
} else {
echo 'Message has been sent.';
}
?>