NodeJS server results in timeout

I have a NodeJS server script, which works like a charm on my local dev environment. But in (beta) production the webserver times out at every request. I've set this up fairly straight forward but I'm unsure how to fix it - or even where to look for a solution. Below is a simplified implementation, my logic for handling post request has been removed. What am I overlooking?

var requestListener = '';
// define the request listener, to handle incoming requests
requestListener = function (req, res) {
    try {
        if (req.method == 'POST') {
            var queryString = '';
            req.on('data', function (data) {
                queryString += data;
            });
            req.on('end', function () {
                // my logic is in here
                res.end(JSON.stringify({ err: false, msg: 'all fine' }));
            });
        }

        res.writeHead(200);
        res.end();
    } catch (error) {
        res.writeHead(400);
        res.end(error);
    }
}

// boot the webserver
server = http.createServer(requestListener);
server.listen(8080);