Controller Naming Convention issue

I have complete a project In CI 3.0.6 , which is works fine in localhost. but when i uploaded it in subdoamin i am getting 

The demo.xyz.com page isn’t working

demo.xyz.com is currently unable to handle this request.


Path:applications/contorllers/Frontend.php

PHP Code:

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

class Frontend extends Frontend_Controller {
    public function __construct ()
    {
        parent::__construct();
        $this->load->model('Banner_m');
           
    
} 


Path:applications/model/Banner_M.php

PHP Code:

class Banner_M extends MY_Model
{
    protected $_table_name = 'banners';
    protected $_order_by = 'id desc';
    
    public function get_new ()
    {
        $banner = new stdClass();
        $banner->title = '';
        $banner->slug = '';
        $banner->target_url = '';
        $banner->banner_img = '';
        $banner->status= '';
        $banner->display_order= '';
        return $banner;
    }
    
    
} 


As i am debugging i got a point that is  the banner model ($this->load->model('Banner_m')) loaded in Frontend Controller.

Thanks.