How to set up error output?

Question

URL Handling

How to set up error output?

I get https://site.ru/faucet/api/an error 403

along the way. I only have a .htaccess file in this path

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

Is it possible to customize this page in this way and how to do it?
If the page just opens in the browser, then it displays a 403 error as it is at the moment, and if a post or a get request comes to this page, then everything works fine.