WordPress Admin Page Issue

Thanks for your quick reply. i have checked and in wp-admin folder index.php is available.
My website is working fine, but wordpress admin panel is not displaying login page.

i also used https://domainname/wp-login.php as well, this shows the login page. But when i enter user-id and pwd, directory listing appears.

kindly suggest.