If you are using nginx for webserver, you need to do this step before the main installation:

• Create a nginx's conf file:

sudo touch /etc/nginx/sites-available/.conf

• Paste this code into that file:

server {
    listen 80;
    listen [::]:80;
    listen 443 ssl;
    listen [::]:443 ssl;

    server_name ;

    ssl_certificate ;
    ssl_certificate_key ;

    location / {
        proxy_pass http://localhost:;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
        proxy_set_header    X-Real-IP $remote_addr;
    }
}

• Link that file to sites-enabled folder:

sudo ln -s /etc/nginx/sites-available/.conf /etc/nginx/sites-enabled/.conf

• Restart the nginx:
  • ubuntu: sudo systemctl restart nginx
  • alpine: sudo service restart nginx

> Done. Now you can go to the main installation!