AsyncTask 스레드에서 HTTP POST전송을 하려하는데,

getOutputStream() 에서 계속 IOException 이 일어나요 ㅠㅠ 왜그럴까요

doInBackGround(String ..params) {

.

.

commURL = new URL("myServerUrl+"phoneNum_regist.php");

urlCon = (HttpURLConnection) commURL.openConnection();

.

.

int resCode = urlCon.getResponseCode();

if(resCode == HttpURLConnection.HTTP_OK) {

String s = "phoneNum=" + params[0];

BufferedWriter send = new BufferedWriter(new OutputStreamWriter(urlCon.getOutputStream()));

send.write(s);

send.flush();

send.close();

Log.e(logtag,"phoneNum_regist Finished!!");

BufferedReader read = new BufferedReader(new InputStreamReader(urlCon.getInputStream()));

return read.readLine().toString();

} else {

return "Failed";

}

.

.

.

catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

urlCon은 잘 연결되어있는데 왜 OutputStream을 못가져오는걸가요 

이것때문에 몇시간째 계속 삽질중이네요 ㅠ.ㅠ 

고수님들 조언부탁드립니다.