HttpURLConnection not working over 3g only wifi

I have created a app that reads a json file across the internet. My app seems to work fine over wifi but when i use 3g it does not work for me on the orange network. I have a friend who tried it on a different network over 3g and it did work. I can browse the internet on 3g so i know i have a connection

I have added some debug code and found that its a IOException file not found if that helps, but why can it find it on wifi?

My code is as follows:

        String addr = "http://policeapi2.rkh.co.uk/api/crimes-street/all-crime?lat=" + strLat + "&lng=" + strLng;
        URL url = new URL(addr);

        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

        String data = "user:password";
    开发者_开发问答    String encoding = Base64.encodeToString(data.getBytes("US-ASCII"), Base64.DEFAULT);

        conn.setRequestProperty ("Authorization", "Basic " + encoding);

        conn.setRequestMethod("GET");

        conn.connect();

        InputStream in = conn.getInputStream();

        BufferedReader reader = new BufferedReader(new InputStreamReader(in));

        String line = null;
        StringBuilder stringBuffer = new StringBuilder();

        while ((line = reader.readLine()) != null) {
            stringBuffer.append(line);
        }