Codeigniter Ajax获得404错误

Question

I wrote an application on my local machine that works perfectly. I am using XAMPP so it is running Apache.

When I uploaded the application to my ubuntu test server, I am getting a 404 error on the ajax call and I am honestly perplexed.

I am using CodeIgniter 3.1.8.

The controller is definitely there and the .htaccess is working fine on my local machine. I checked the case of the filename for the controller and it is fine.

Here's the javascript of the ajax call:

function step2(){
    var canShow = false;    
    var cCode = $("#student_code").val();
    $.ajax({
        url: "/decide/ajaxStep2",
        data: {"student_code": cCode, "lang": "<?=$lang?>"},
        method: "post",
        success: function(data){
        }
    });
}

The controller definition and applicable function (just to show it exists... I don't think the internal code is relevant):

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

class Decide extends MY_Controller {
    function ajaxStep2(){
        //Code here
    }

}

I have done reading and I see some stuff related to the routes file but again I come back to the fact that it works fine on my local machine. I don't think it's file permissions because the index() method runs fine.

I have used ajax a lot and I have never had this issue before so I am honestly not sure where to even look on this. Any thoughts?