problem with uploading CI on the web server

Hi. I have some problems with upload my CI project on the web server. Until now I hosted it only locally on my xampp but i wanted to upload this on the web.
But it's not working.
I thought it was some config.php issue, but after that I've uploaded vanilla CI 3 to test if it's works. So the welcome controller works fine. but when i've created some test controller like:

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class hello extends CI_Controller {

public function index()
{
echo 'aaaa';
}
}

After that i've entered http://mydomain.com/index.php/hello .
So it should print 'aaaa', right? But it didn't. It's just shows 404 error page. And I have this issue with every controller.

Am I doing something wrong? Did I missed something? Any ideas or anything?
Thank you for your help.

Yes http://www.codeigniter.com/userguide3/ge...ello-world

Yes, read the notes in the link gadelat posted.

Controller Filename MUST be "Hello.php" (cap first letter)
Controller definition MUST be "class Hello extends CI_Controller" (first letter of classname upper case)

Windows doesn't care about upper/lowercase filenames, but just about everything else in the world does