throw new NotFoundHttpException and Not allowed actions are being redirected to application default action

Whenever there is throw new NotFoundHttpException or Not allowed actions(because the user has not logged in) when I send any request the response is being the website default page.

I don’t understand why is it acting like that but I would like those two response to be considered as error to ajax resquest and to not send the website as response.

How can I do that?

I am think may be it my .htaccess configuration? of which I am not sure.

# if a directory or a file exists, use it directly

RewriteCond %{REQUEST_FILENAME} !-f

RewriteCond %{REQUEST_FILENAME} !-d

# otherwise forward it to index.php

RewriteRule . index.php