node-http-proxy "Error: read ECONNRESET"

var util = require('util'),
    http = require('http'),
    httpProxy = require('http-proxy');
    
function request_handler(proxy, req, res) {
  // http(s) requests.
  proxy.web(req, res, function (err) {
      console.log(err.stack);
      res.writeHead(502);
      res.end("There was an error. Please try again");
  });
  // websocket requests.
  req.on('upgrade', function (req, socket, head) {
    proxy.ws(req, socket, head, function (err) {
      console.log(err.stack);
      socket.close();
    });
  });
}

var site_host_http = "http://localhost:8000";

// create the HTTP proxy server.
var http_proxy = httpProxy.createProxyServer({
  target: site_host_http, ws:true
});

// listen to error
http_proxy.on('error', function (err, req, res) {
  res.writeHead(500, {
    'Content-Type': 'text/plain'
  });

  res.end('Something went wrong. And we are reporting a custom error message.');
});

// launch http server.
var http_server = http.createServer(function(req, res) {
  request_handler(http_proxy, req, res);
});
http_server.on('listening',function() {
    console.log('ok, http proxy server is running');
});
http_server.listen(80);

util.puts('http proxy server started on port 80');