Socket.io returns to XHR poll

I have an Express, Node and Socket.io app, when I check the Network I see that the Socket is falling back to XHR reuqests and not WebSockets.

Am I missing something obvious?

In my console, I see that on my Networks tab, I don't see the WebSocket, just XHR requests to socket.io:

WebSocket connection to 'ws://localhost/socket.io/?EIO=3&transport=websocket&sid=lVFuwHcH-XPm8zHhAAAA' failed: Error in connection establishment: net::ERR_SOCKS_CONNECTION_FAILED

      

        
        
        
      

    

Server code:

var app         = express(),
    http        = require('http').Server(app),
    io          = require('socket.io')(http),

io.on("connection", function (socket) {
    var interval = setInterval(function () {
        if(nt == ""){
            socket.emit("message", {"data": "<strong>Waiting for data...</strong>"});
        }else{
            socket.emit("data", {
                "mediumLoadTime": nt.mediumPageLoad(),
                "firstLoadTime": nt.times[0],
                "lastLoadTime": nt.times[nt.times.length-1],
                //"times": nt.times,
                "requests": nt.reqMade.toString(),
                "success": nt.successful.toString(),
                "error": nt.error.toString(),
                "virtualusers": nt.virtualUsers.toString(),
                "host": nt.options.host.toString(),
            });
        }
    }, 10);

    socket.on("disconnect", function () {
        clearInterval(interval);
    });
});

      

        
        
        
      

    

Customer:

var socket = io();


   socket.on('data', function (data) {
        console.log(data);
   });

      

        
        
        
      

    

In my opinion, I need <script src="https://cdn.socket.io/socket.io-1.2.0.js"></script>