I want to return a JSON response instead of the default 404 error page when **ModelNotFoundException** occurs. To do this, I wrote the following code into `app\Exceptions\Handler.php` :

```
public function render($request, Exception $exception)
{
    if ($exception instanceof ModelNotFoundException) {
        return response()->json([
            'error' => 'Resource not found'
        ], 404);
    }

    return parent::render($request, $exception);
}

```

However it doesn't work. When the **ModelNotFoundException** occurs, Laravel just shows a blank page. I find out that even declaring an empty render function in `Handler.php` makes Laravel display a blank page on **ModelNotFoundException**.

How can I fix this so it can return JSON/execute the logic inside the overriden render function?