Help with PHPMailerAutoload.php

I am trying to send an email using the php library that is PHPMailerAutoload.php The reason I use this library is to retrieve a user's password. NOTE: I am using gmail. I have the code configured this way:

//Método getValor
function getValor($campo, $campoWhere, $valor) {
$ConexionBD = con();

$stmt = $ConexionBD->prepare("SELECT $campo FROM cliente_correo WHERE $campoWhere = ? LIMIT 1");
$stmt->bind_param('s', $valor);
$stmt->execute();
$stmt->store_result();
$num = $stmt->num_rows;

if ($num > 0) {
    $stmt->bind_result($_campo);
    $stmt->fetch();
    return $_campo;
}
else {
    return null;    
}
}

function enviarEmail($email, $nombre, $asunto, $cuerpo){
require 'php/PHPMailer/PHPMailerAutoload.php';

$mail = new PHPMailer();
$mail->isSMTP();
$mail->SMTPDebug = 2;
$mail->SMTPAuth = true;
$mail->SMTPSecure = 'tls';
$mail->Host = 'smtp.gmail.com';
$mail->Port = 587;

$mail->Username = '[email protected]';
$mail->Password = '*************';

$mail->setFrom('[email protected]'); //REMITENTE 
$mail->addAddress($email, $nombre); //DESTINATARIO

$mail->Subject = $asunto;
$mail->Body    = $cuerpo;
$mail->IsHTML(true);

//ENVIO DEL EMAIL ...
if($mail->send() == false) {
    //return true;
    echo "No se pudo enviar ";
    echo "Error de PHPMailer  ".' '.$mail->ErrorInfo;
}
else {
    //return false;
    echo "El correo se envió ;)";
}

}

My HTML form:

<form method="POST" action="<?php $_SERVER['PHP_SELF']; ?>" role="form" class=" form-horizontal login-form">        
            <fieldset>
                <div class="login-wrap">
                    <p class="login-img"><i class="icon_lock_alt"></i></p>
                    <div class="input-group">
                        <span class="input-group-addon"><i class="icon_profile"></i></span>
                        <input type="email" name="recover_mail" class="form-control" 
                               placeholder="Introduce tu correo electrónico" required >
                    </div>
                    <button class="btn btn-primary btn-lg btn-block" type="submit" name="enviar_email">Enviar</button>
                </div>
                <div class="panel-footer">
                    ¿No te has registrado? <a href="cliente_registrar.php">Registrate ahora</a>
                </div>
            </fieldset>
</form>

The POST method I have it like this:

if(!empty($_POST)) {
$email = mysqli_real_escape_string($ConexionBD, $_POST['recover_mail']);

if(!isEmail($email)) {
    $errors[] = "Debe ingresar un email valido";
}

if(emailExiste($email)) {
    //hace una consulta a la tabla cliente_correo
    $user_id = getValor('idCliente', 'correoElectronico', $email);
    $correoElectronico = getValor('correoElectronico', 'correoElectronico', $email);

    $url = 'http://'.$_SERVER["SERVER_NAME"].'/Monte-Carlo_v5/cliente_pass_change.php?user_id='.$user_id;

    $asunto = 'Recuperar Password';
    $cuerpo = "Hola $email:<br><br>Se ha solicitado un reinicio de contrase&ntilde;a, por favor, para procesar este paso haz clic a la siguiente direcci&oacute;,: 
        <a href='$url'>Ok, Cambiar Password!!</a> ";

    if(enviarEmail($email, $correoElectronico, $asunto, $cuerpo)) {

        echo '
            <p class="text-success">Hemos enviado un correo electrónico a la direccion $email para restablecer tu password.</p>
            <br><br>
            <a href="cliente_login.php">Iniciar sesion</a>
            ';

        exit;
    } else {
        $errors[] = "Error al enviar email";
    }
} else {
    $errors[] = "El email no existe";
}

}

And this is the error that I have