2 factor authentication with ajax request


I'm currently writing an 2FA app for owncloud, I load a script on the challenge.php page that should contact the owncloud server using an ajax request to do the authentication but I always get an HTTP 303 status.

Below is the code I use in the script :

function ajaxRequest(params)
        url: OC.generateUrl('/apps/myapps/echo'),
        type: 'POST',
            echo: "test",
        dataType: 'json',
        success: function(response) { console.log(response.echo);}
        error: function() { console.log('error sp');}
    return false;

The route in routes.php is : ['name' => 'page#do_echo', 'url' => '/echo', 'verb' => 'POST']

And for the page controller (PageController.php), the function is :

 * @NoAdminRequired
public function doEcho ($echo)
    return new DataResponse(['echo' => $echo]);

So far the only answer I got from my server is an 303 http status. Did I miss something when writing my code ?