How to allow a site to work with 2 ports 80 and 443?

Question

Nginx

I can’t allow the site to work on 2 ports. The situation is this, after visiting the site via https and deleting the letter s, that is, try to immediately enter via http, it redirects to https although there is no 301 redirect. But if you go from a clean tab via the http protocol, then it starts to download index.php, "Untitled" is the file name.
Here is the code:

server {
    listen 80;
    listen [::]:80  ipv6only=on;

    listen 443 ssl;
    listen [::]:443 ssl ipv6only=on; 
 

    server_name   bellovera.ru;
    include letsencrypt.conf;

Answer 1

The browser can remember that this site has HTTPS and even without a server redirect choose HTTPS
https://www.zdnet.com/article/google-is-running-an...

Answer 2

miracles don't happen. if it redirects, then there is a redirect somewhere. I see 4 options:
1. info is left in the browser cache.
2. redirect in the nginx config
3. redirect in the backend config - for example, apache, if it exists.
4. redirect in the site code.