nginx - 80端口不能使用!

1: 新一rails项目配置nginx如下:

server {
    listen 80;
    server_name gui;
    root /opt/dev/gui/public;   # <--- be sure to point to 'public'!

    client_max_body_size 10M;

    passenger_enabled on;

    passenger_use_global_queue on;
    rails_env devlopment;

    access_log   /opt/dev/gui/log/nginx.access.log ;
    error_log    /opt/dev/gui/log/nginx.error.log ;


    # disable site via capistrano (cap deploy:web:disable)
    if (-f $document_root/system/maintenance.html) {
        rewrite ^(.*)$ /system/maintenance.html break;
    }

  error_page   500 502 503 504  /500.html;

    # expires headers, takes advantage of the Rails asset_tag helpers:
    location ~* ^.+\.(ico)(\?[0-9]+)?$ {
        passenger_enabled off;
        expires max;
    }

}

2: nginx -s reload

3: 浏览器中输入:http://gui 怎么进不了我的应用呢