将Slim项目上传到服务器后，我收到错误403，我该如何解决？

Here is my slim project Structure

-demosetup
     -app
     -bootstrap
       --- start.php
     -config
     -database
     -public
         ---- .htaccess
         ---- index.php
     -resources 
     -routes
     -vendor 
     -.env
     -composer.json
     -composer.lock 

In my .htaccess file

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^ index.php [QSA,L]

In my index.php file

require_once __DIR__ . '/../bootstrap/start.php';

$app->run();

In my start.php file

use App\App;

session_start();
require_once __DIR__ . '/../vendor/autoload.php';

$app = new App;

require_once __DIR__ . '/../database/db.php';
require_once __DIR__ . '/../routes/website.php';

I'm having the 403 Forbidden error problem while upload the whole slim 3 project to the server. Im using cPanel goDaddy Hosting site for my server. My server php version is 5.6 , so I'm pretty sure it support all the slim framework version.

All my floder premission are set to 0755 and file are set to 0644.

What am I doing it wrong? I have been trying to figure out the whole day with no luck.

Forbidden

You don't have permission to access / on this server. Additionally, a 403 Forbidden error was encountered while trying to use an ErrorDocument to handle the request.