server {
    listen 80;
    server_name _; # 通配符，表示匹配所有服务器名

    location ^~ /.well-known/acme-challenge/ {
        default_type "text/plain";
        root /var/www/letsencrypt; # 确保这里的路径指向您存放ACME挑战文件的目录
    }
        # Redirect all other requests to HTTPS
    location / {
        return 301 https://$host$request_uri;
    }
    # 保留现有的其它配置 ...
}