Node.js Apache-websocket握手时出错，意外响应代码：502

我有以下Apache设置，但由于以下错误而失败：

WebSocket连接到'wss://mydoain.com/socket.io/1/websocket/zpxKUhj9zN3MsTdXIkrL'失败：WebSocket握手期间出错：意外响应代码：502

#Server version: Apache/2.2.15 (Unix)
#Server built:   Jul 23 2014 14:17:29

NameVirtualHost *:443
<VirtualHost *:443>
  Header set Access-Control-Allow-Origin: "https://from.mydomain.com"
  SSLEngine on
  SSLProxyEngine On
  ProxyPreserveHost On

  SSLProtocol all -SSLv2
  SSLCipherSuite ALL:!ADH:!EXPORT:!SSLv2:RC4+RSA:+HIGH:+MEDIUM:+LOW
  SSLCertificateFile /etc/key.crt
  SSLCertificateKeyFile /etc/key.key
  SSLCertificateChainFile /etc/key.ca

  ServerName to.mydomain.com
  ServerAlias to.mydomain.com
  ProxyPass / http://localhost:8888/
  ProxyPassReverse / http://localhost:8888/
  #ProxyPassReverseCookiePath /MYSITE/ /
        CacheDisable *
</VirtualHost>

服务器版本：Apache/2.2.15（Unix） #服务器构建时间：2014年7月23日14:17:29 名称虚拟主机*：443 标题集访问控制允许原点：“https://from.mydomain.com" 斯伦金安 SSLProxyEngine打开 代理主机 SSLProtocol all-SSLv2 SSLCipherSuite全部：！ADH:！出口：！SSLv2:RC4+RSA:+HIGH:+MEDIUM:+LOW SSLCertificateFile/etc/key.crt SSLCertificateKeyFile/etc/key.key SSLCertificateChainFile/etc/key.ca ServerName to.mydomain.com ServerAlias to.mydomain.com ProxyPass/http://localhost:8888/ ProxyPassReverse/http://localhost:8888/ #ProxyPassReverseCookiePath/MYSITE// 缓存禁用* 注意：

http://localhost:8888

是基于websocket的信令服务器