server {
    listen 80;
    listen [::]:80;
    server_name __DOMAIN__;

    root /var/www/acme;

    location /.well-known/acme-challenge/ {
        default_type "text/plain";
        try_files $uri =404;
    }

    location / {
        return 200 'ok';
        add_header Content-Type text/plain;
    }
}