PHP error: SMTP Error: Could not authenticate - php

Question

I tried to create a mail-confirm signup system but when I signup, database save my data but there is a error that says:
SMTP Error: Could not authenticate.
note: I am using class.phpmailer.php
I could not understand the problem. Here is my code:
sendmail.php
<?php
require 'PHPMailerAutoload.php';
function send_mail($sendto, $subject, $body)
{
$mail = new PHPMailer;
//$mail->SMTPDebug = 2; // Enable verbose debug output
$mail->isSMTP(); // Set mailer to use SMTP
$mail->Host = 'smtp.gmail.com'; // Specify main and backup SMTP servers
$mail->SMTPAuth = true; // Enable SMTP authentication
$mail->Username = '**.****.****#gmail.com'; // SMTP username
$mail->Password = '**********'; // SMTP password
$mail->SMTPSecure = 'ssl'; // Enable TLS encryption, `ssl` also accepted
$mail->Port = 465; // TCP port to connect to
$mail->setFrom('e.d***.c**#gmail.com', 'Restro | Restaurants in Mumbai');
$mail->addAddress($sendto); // Name is optional
$mail->addReplyTo('e.d****.c***#gmail.com', 'Restro | Restaurants in Mumbai');
$mail->isHTML(true); // Set email format to HTML
$mail->Subject = $subject;
$mail->Body = $body;
$mail->AltBody = 'Please open this on Chrome';
if (!$mail->send()) {
//echo 'Message could not be sent.';
return 'Mailer Error: ' . $mail->ErrorInfo;
} else {
return 'Message has been sent';
}
}

Answer 1

Use port 465
port 587 if your client begins with plain text before issuing the STARTTLS command.