连接失败：ECONNREFUSED HttpURLConnection POST内部服务器Android

Question

My Native Android Application调用我的组织内部服务器中托管的Web服务，该服务在我们的网络中运行。

我使用Async任务使用HttpURLConnection进行HTTP POST连接。当我执行DataOutputStream wr = new DataOutputStream(conn.getOutputStream());时，它正在提供java.net.ConnectException: failed to connect to /10.xxx.xxx.xxx (port 90): connect failed: ECONNREFUSED (Connection refused)

try {

    for (String currentUrl : urls) {
        // 1. URL
        URL url = new URL(currentUrl);

        // 2. Open connection
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

        // 3. Specify POST method
        conn.setRequestMethod("POST");

        conn.setRequestProperty("User-Agent", USER_AGENT);

        conn.setRequestProperty("Accept-Language", "en-US,en;q=0.5");

        // 4. Set the headers

            conn.setRequestProperty("Content-Type", "application/json");


        conn.setDoOutput(true);

        // 5. Add JSON data into POST request body

        DataOutputStream wr = new DataOutputStream(conn.getOutputStream());

        wr.writeBytes(requestObject.toString());

        wr.flush();

        wr.close();

        // 6. Get the response
        int responseCode = conn.getResponseCode();

        System.out.println("\nSending 'POST' request to URL : " + url);

        System.out.println("Response Code : " + responseCode);

        BufferedReader in = new BufferedReader(
                new InputStreamReader(conn.getInputStream()));

        String inputLine;

        StringBuffer response = new StringBuffer();

        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        // 7. Print result
        System.out.println(response.toString());
    }

} catch (MalformedURLException e) {

    e.printStackTrace();


} catch (IOException e) {

    e.printStackTrace();

}

我哪里错了？请建议我