function mmk_pending_review_redirect(){
        $user = wp_get_current_user();
        if(get_post_status ( get_the_id() ) != \'publish\')
            if (is_user_logged_in() && !in_array( \'administrator\', (array) $user->roles ) && !is_author() ) {
                wp_redirect( "https://example.com/under-approval");
                exit;
            }else{
              wp_redirect( "https://example.com/under-approval") );
              exit;
            }
        }
    }
add_action(\'template_redirect\', \'mmk_pending_review_redirect\');