Codeigniter An unrelated exception was encountered Type: RuntimeException does not work on Linux server

Building a website using codeigniter . All codes work in (XAMPP) . localhost

But the same code fails on server Linux

showing error like

An unrelated exception was caught

Type: RuntimeException

Message: Could not find the specified model: Admin_user

File name: /home/capitalw/public_html/domain/system/core/Loader.php

Line number: 344

Backtrace:

File: /home/capitalw/public_html/domain/application/controllers/Admin.php Line: 10 Function: model

File: /home/capitalw/public_html/domain/index.php Line: 315 Function: require_once

Here are my codes

applications / controller / admin.php

class Admin extends CI_Controller {

    public function __construct(){
        parent::__construct();
        //$this->load->library('common');
        $this->load->library('form_validation');
        $this->load->model('admin_user');

    }
}

      

        
        
        
      

    

applications / models / admin_user.php

class Admin_user extends CI_Model {

    function __construct()
    {
        parent::__construct();

    }
//some inser update codes here


}