401 Encountered when generating token with client_credentials Java 6 EE

Question

I tried to use the following method which is used in other areas of the app but I still get 401:

The original question is posted here: Java 6 EE Client Credentials Bearer

  String urlParameters = "client_id=CLIENT_ID&client_secret=CLIENT_SECRET&grant_type=client_credentials";
  byte[] postData = urlParameters.getBytes("UTF-8");
  int postDataLength = postData.length;
  String TokenURL = "URL for getting the token here";
  URL url = new URL(TokenURL);
  HttpURLConnection conn = (HttpURLConnection) url.openConnection();
  conn.setDoOutput(true);
  conn.setInstanceFollowRedirects(false);
  conn.setRequestMethod("POST");
  conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
  conn.setRequestProperty("charset", "utf-8");
  conn.setRequestProperty("Content-Length", Integer.toString(postDataLength));
  conn.setUseCaches(false);
  DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
  wr.write(postData);
  wr.flush();
  System.out.println("->->-> We will send: " + urlParameters);
  if (conn.getResponseCode() != HttpURLConnection.HTTP_CREATED && conn.getResponseCode() != HttpURLConnection.HTTP_OK) {
      System.out.println("->->-> Returned Http Code: " + conn.getResponseCode());
      throw new RuntimeException("Failed : HTTP error code for Getting Token XFORMURLENCODED : " +
          conn.getResponseCode());
  }