I’m going to host the site on your hosting. It should be set up like this: the user opens the main page and sees the login form. He enters a username and password (which he cannot get himself through registration, this must be passed on by the admin, that is, me). If this data is correct, the subdomain page opens with the main content. If they are incorrect, the 403 Forbidden error will open. That’s just how to implement it without .htaccess (login with it can be configured only by IP addresses, but I need it to be by login and password). Please help me. And yes, sorry for my English, I use a translator.