docker-automatic-nginx-letsencrypt/extra/default-server.conf

server {
    listen 80 default_server;
    listen [::]:80 default_server;

    server_name _;

    # From: https://community.letsencrypt.org/t/how-to-nginx-configuration-to-enable-acme-challenge-support-on-all-http-virtual-hosts/5622
    location ^~ /.well-known/acme-challenge/ {
        default_type "text/plain";
        alias /letsencrypt/well-known/;
    }

    # Hide /acme-challenge subdirectory and return 404 on all requests.
    # It is somewhat more secure than letting Nginx return 403.
    # Ending slash is important!
    location = /.well-known/acme-challenge/ {
        return 404;
    }

    # Redirects all default HTTP traffic to HTTPS.
    location / {
      return 301 https://$host$request_uri;
    }
}