Opencart SSL e Access Origin

index.php

if($_SERVER['HTTP_HOST'] == 'mercadogun.com' || $_SERVER['HTTP_HOST'] == 'www.mercadogun.com') {
    echo('<center>Em breve!</center>');
    die();
}

// Redireciona para https
if (empty($_SERVER['HTTPS']) || $_SERVER['HTTPS'] === "off") {
    $location = 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
    header('HTTP/1.1 301 Moved Permanently');
    header('Location: ' . $location);
    exit;
}

header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET, POST');
header("Access-Control-Allow-Headers: Content-Type");

if ($_SERVER['REQUEST_METHOD'] == 'OPTIONS')
    exit;

// If is JSON request
$json_payload = json_decode(file_get_contents('php://input'), true);
if($json_payload != NULL) {
    $_POST = $json_payload;
}