Codeigniter 中的分页返回错误

我的问题是分页不起作用，它完美地显示了页数<<1 2 3>>等......但是当我尝试进入第 2 页时，它给了我一个错误，例如：

The requested URL /mysite/welcome/index/2 was not found on this server.

这是我的模型叫做：国家.php

<?php
defined('BASEPATH') OR exit('No direct script access allowed');
class Country extends CI_Model
{
public function __construct() {
    parent::__construct();
}
public function record_count() {
    return $this->db->count_all("news");
}
public function fetch_countries($limit, $start) {
    $this->db->limit($limit, $start);
    $query = $this->db->get("news");
    if ($query->num_rows() > 0) {
        foreach ($query->result() as $row) {
            $data[] = $row;
        }
        return $data;
    }
    return false;
   }
}

这是我的控制器，它在页面上显示新闻和分页，但不幸的是，正如我所说，当我尝试转到第 2 页时，它会返回一条错误消息。

我的控制器呼叫欢迎.php

 class Welcome extends CI_Controller {
/**
 * Index Page for this controller.
 *
 * Maps to the following URL
 *      http://example.com/index.php/welcome
 *  - or -
 *      http://example.com/index.php/welcome/index
 *  - or -
 * Since this controller is set as the default controller in
 * config/routes.php, it's displayed at http://example.com/
 *
 * So any other public methods not prefixed with an underscore will
 * map to /index.php/welcome/<method_name>
 * @see https://codeigniter.com/user_guide/general/urls.html
 */
public function __construct()
{
    parent::__construct();
    $this->load->model('news_model');
    $this->load->helper('url_helper');
    $this->load->model("Country");
    $this->load->library("pagination");
}

public function index()
{
    $config = array();
    $config["base_url"] = base_url('') . "welcome/index";
    $config["total_rows"] = $this->Country->record_count();
    $config["per_page"] = 2;
    $config["uri_segment"] = 3;
    $this->pagination->initialize($config);
    $page = ($this->uri->segment(3)) ? $this->uri->segment(3) : 0;
    $data["results"] = $this->Country->
        fetch_countries($config["per_page"], $page);
    $data["links"] = $this->pagination->create_links();
    $data['news'] = $this->news_model->get_news();
    $data['title'] = 'News archive';
    $this->load->view('index', $data);
}
public function view($slug = NULL)
{
    $data['news_item'] = $this->news_model->get_news($slug);
    if (empty($data['news_item']))
    {
            show_404();
    }
    $data['title'] = $data['news_item']['title'];
    $this->load->view('view', $data);
}
}

是默认路由

 $route['default_controller'] = 'welcome';

我也可以在主页上看到我的新闻和分页：

localhost/mysite

我希望我很清楚，请帮助我为什么分页不起作用。

感谢您的帮助。