我目前正在学习使用Java中的API，我正在使用汇率API，但是，它无法理解发生了什么，我发送了所有请求的参数，我还发送了我的API密钥作为头部。

private static void sendHttpGETRequest(String fromCode, String toCode, double amount) throws IOException, JSONException{
        
        String GET_URL = "https://api.apilayer.com/exchangerates_data/convert?to="+toCode+"&from="+fromCode+"&amount="+amount;        

        URL url = new URL(GET_URL);
        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
        httpURLConnection.setReadTimeout(200 * 1000);
        httpURLConnection.setConnectTimeout(200 * 1000);                
        
        httpURLConnection.setRequestMethod("GET");
        httpURLConnection.setRequestProperty("apikey", "MyApiKeY");
        int responseCode = httpURLConnection.getResponseCode();
        
        System.out.println("Response code: " + responseCode);
                
        if(responseCode == httpURLConnection.HTTP_OK){//SUCESS
            BufferedReader in = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));
            String inputLine;
            StringBuffer response = new StringBuffer();
            
            while((inputLine = in.readLine()) != null){
                response.append(inputLine);
            }in.close();             
            
            JSONObject obj = new JSONObject(response.toString());
            Double exchangeRate = obj.getJSONObject("rates").getDouble(fromCode);
            System.out.println(obj.getJSONObject("rates"));
            System.out.println(exchangeRate); //keep for debugging
            System.out.println();
            
        } 
        else {
            System.out.println("GET request failed");
        }                                          
    }

我已经使用setConnectTimeout和setReadTimeout来设置网络超时，认为这是问题所在，但仍然得到相同的错误。