Phpmailer tidak bisa connect ke smtp (PHPMailer 5.2-stable)

Kode Error: Message could not be sent.Mailer Error: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting

<?php
require 'PHPMailer/PHPMailerAutoload.php';

$mail = new PHPMailer;

//$mail->SMTPDebug = 3;

$mail->isSMTP();
$mail->Host = 'smtp.gmail.com';
$mail->SMTPAuth = true;
$mail->Username = 'Emailku@gmail.com';
$mail->Password = 'Passwordku';
$mail->SMTPSecure = 'tls';
$mail->Port = 587;

$mail->setFrom('Emailku@gmail.com', 'Website Rayyan Verifikasi');
$mail->addAddress('Emailtujuan@gmail.com');

//$mail->addAttachment('File');
$mail->isHTML(true);

$mail->Subject = 'Verifikasi Alamat Email';
$mail->Body    = '<style>
	html{
		background: #E7E7E7;
	}
	#frm{
		border: solid gray 1px;
		width: 25%;
		border-radius: 5px;
		margin: 100px auto;
		background: white;
		padding: 10px;
	}
	#teks{
		text-align: center;
		font-family: arial;
	}
	#btn{
		width: 100px;
		margin-right: 35%;
		margin-left: 35%;
		height: 50px;
		background: #B4B4B4;
		border-color: black 1px;
		border-radius: 5px;
		padding: 5px;
		font-family: arial;
		text-align: center;
	}
	#link{
		text-decoration: none;
		color: black;
		font-size: 35px;
	}
	#url{
		background: black;
		color: white;
		border-radius: 5px;
		padding: 3px;
		font-family: arial;
		text-align: center;
	}
</style>
<div id="frm">
	<h1 id="teks">Verivikasi Kode</h1>
	<p id="teks">Klik tombol dibawah ini</p>
	<button id="btn"><a href="Link tujuan" id="link">Verify</a></button>
	<p id="teks">Atau copy url di bawah ini dan paste di browser</p>
	<div id="url"><p>Link tujuan</p></div>
</div>';

if(!$mail->send()) {
    echo 'Message could not be sent.';
    echo 'Mailer Error: ' . $mail->ErrorInfo;
} else {
    echo 'Message has been sent';
}
?>

Jawab ya