SilverStripe Ajax request rendering partial view with renderWith is not working

Questions
1

I am developing a SilverStripe project. In my project, I am trying to make an Ajax request to the controller and render the partial view. I am following this tutorial, https://www.silverstripe.org/learn/lessons/v4/ajax-behaviour-and-viewabledata-1. But it is not working. Please, see my code below.

This is my index function in the controller

public function index(HTTPRequest $request)
{
    if ($request->isAjax()) {
        return $this->renderWith('Authors');
    }

    return [
        'Blogs' => $this->getBlogs(),
    ];
}

As you can see in the code, I am trying to render the Authors partial view in the Includes folder.

I created the partial view in the Includes folder in the templates folder with the following code.

<h1>This is the previous events partial view.</h1>

This is how I make ajax call in Jquery

$.get(url)
            .then(function (response) {
                //render the view here

            })
            .catch(function (error) {
                console.log(error);
            })

But the ajax call is throwing an error. This is the error.

[User Warning] None of the following templates could be found: cyber-duck/templates/PreviousEvents in themes "Array ( [0] => my-themes [1] => $default ) "
GET /upcoming-events?page=2
Line 210 in /var/www/public/vendor/silverstripe/framework/src/View/SSViewer.php

Source
201             $message .= print_r($templates, true);
202 
203             $themes = self::get_themes();
204             if (!$themes) {
205                 $message .= ' (no theme in use)';
206             } else {
207                 $message .= ' in themes "' . print_r($themes, true) . '"';
208             }
209 
210             user_error($message, E_USER_WARNING);
211         }
212     }
213 
214     /**
215      * Triggered early in the request when someone requests a flush.
216      */

What is the issue and how can I fix it?