我已经创建了一个windows amazon ec2示例并在其上安装了一个flask应用程序。localhost打开了所需的主页。然后使用waitress-serve托管app.py文件，并使用nsm创建了一个服务。之后，我下载并执行了nginx.exe。现在我的ec2公共ip显示了nginx主页。修改nginx.conf后我希望看到的是主页而不是nginx主页，但我仍然看到了nginx主页。以下是我的nginx.conf文件文本

worker_processes  1;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;

events {
    worker_connections  1024;
}

http {
    #include /etc/nginx/sites-enabled/*;
    #include       mime.types;
    #default_type  application/octet-stream;

    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    #sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;
    
    upstream flaskhelloworld {
        server 127.0.0.1:5000;
    }

    # another virtual host using mix of IP-, name-, and port-based configuration
    #
    server {
        listen 80 default_server;
        server_name my_public_ip;
        listen  [::]:80 default_server;

        root /var/www/html;

        server_name _;

        location / {
            proxy_pass http://flaskhelloworld;
        }
    }

    # HTTPS server
    #
    #server {
    #    listen       443 ssl;
    #    server_name  localhost;

    #    ssl_certificate      cert.pem;
    #    ssl_certificate_key  cert.key;

    #    ssl_session_cache    shared:SSL:1m;
    #    ssl_session_timeout  5m;

    #    ssl_ciphers  HIGH:!aNULL:!MD5;
    #    ssl_prefer_server_ciphers  on;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}

}