ช่วยผมด้วยส่งเมลไม่ได้ PHPMailer แนะนำด้วยครับ(SMTP Error: Could not authenticate.)

<?php

	require_once('PHPMailer_v5.1/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->FromName = "Nan";  // set from Name
					$mail->Subject = "Engineer";  //หัวเรื่อง
					$mail->Body = " test test teste teste sttestetstetstetstetetstestset";
			 
					$mail->AddAddress("[email protected]"); // to Address

	$mail->Send();
?>