Ajax Request Error and jQuery Versions

Question

I’m having a problem understanding and solving a problem with a request Ajax that I need to do. Below is a list of the sequence of the subject that I will say:

• Explain what I need;
• Explain what I want to do;
• Show how it is currently;
• Present the solutions I’ve tried;

First: I’m developing a travel site where this site has a navbar, in this navbar there is a menu called 'Information'. I happen to have a platform/system that the user accesses and creates an article that is inserted as a Menu item Dropdown every time he creates a new article (the menu has a while).

What I need and want to do is: every time the visitor clicks on one of these items/menus from the Drop Menu, he opens a Bootstrap modal with the customer-made article information. Right?

That’s the general idea. Well, what I need is just to take that information from the database (what I’ve already done) and present it on a page. php (which I’ve also done, is called Response.php). This page only displays text written by the user without any style (done already in the modal or at the time of article creation). What I can do is call this page via Javascript with the jQuery and Ajax (which is what I want to do). However this is my problem and I don’t know exactly where I need to see. Below

Point of Problem: 1st: the version of jQuery used is 2.1.4 (another dev worked before and stayed with this one), and I tested using a more current version. The result was that the request only worked that other plugins that use jQuery stopped working or were not recognized.

2nd: There are 2 types of links for the site: 1 is with the domain itself here (www.dominioproprio.com/). When so, the request appears normally, however when accessing the client’s actual website (www.sitedocliente.com.br), the request when it is made, it crashes and does not go to Success.

3rd: When I try to use the link manually of the request:

www.sitedocliente.com.br/Response? page_id=123

the result is:

The requested URL /Sponse was not found on this server.

This is already taking me out of the picture and I’ve compared it with other uses of my ajax and it’s ok.

Below is some information from the JS request:

$("[data-page-id]").click(function(){
let page_id=$(this).attr("data-page-id");
let response=$(".response-content");
response.html("<div class='text-center'><i class='fa fas fa-cog fa-spin fa-5x'></i>");
setTimeout(function(){
    $.ajax({
        url:link+"/response?page_id="+page_id,
        type:'GET',
        success:function(data){
        $(response).html(data);
        }
    });
},200); 
});

And now we have also how it is in HTML display of this attribute data-page-id: I put it very rudimentary because I don’t have access to the server but rewrote it to understand:

<ul>
        <?php 
            while($pagina = $paginas->fetch_object()){
                <li>
                    <a href="#" data-toggle="modal" data-target="#modal_response" data-page-id="<?= $pagina->id ?>"></a>
                </li>
            }
        ?>
</ul>

This variable $pagina receives the results of the PAGES table containing the articles written by the client (article sounds strong, is more a message in a modal ^^ ).

Moreover, $pagina->id is in the data-page-id because this will be the reference of each LI created.

Infos:

link is a javascript variable that is receiving the current site;

This is the code of the Sponse page that presents the article in the modal

<?php
    $_GET = $db->Escapar($_GET);

    if(!isset($_GET['page_id'])) 
        die("ID não encontrado");

    $page_id = $_GET['page_id'];

    $pagina = $db->Executar("SELECT * FROM paginas WHERE adm_id=$adm_id AND id=$page_id");

    if($pagina->num_rows == 0) die("ID não encontrado");
        $pagina = $pagina->fetch_object();

?>

<!--<img style="margin: 0 auto; max-height: 250px; display: block" src="<?=$pagina->avatar?>"/>-->
<br>
<?=$pagina->pagina; ?>

Is this information enough? Tell me what you think and how I can correct.

Grateful!

EDIT 1: Before you ask me or not haha... The URI /response?page_id=01 doesn’t have the .php because of this little cutie here:

if($url[0] == "response") {
    include "response.php";
    exit();
}

EDIT 2: Now that I have already informed enough to understand the operation and that in my view is correct, I need to know why the request can not access from the client site, only from my server, and everything is equal and loaded there?