Android Volley SSL错误

我在同一台服务器上使用两个嵌套的凌空请求，但第二个则返回错误：

        StringRequest strReqUpdate = new StringRequest(Request.Method.GET, versionCheckURL, new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {
            initJson = response;
            try {
                JSONObject root = new JSONObject(initJson);
                final long version = root.getLong("latest_update");                  
                long localVersion = prefs.getLong("version", 0);
                boolean flag = false;

                if(version != localVersion){                    
                        flag = true;
                }

                if(flag == true){                     
                    StringRequest strReq = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
                        @Override
                        public void onResponse(String response) {                               
                            SharedPreferences.Editor editor = prefs.edit();
                            editor.putString("json", response);                                                                                              
                            editor.putLong("version", version);
                            editor.commit();

                            parseData(response); 
                        }
                    }, new Response.ErrorListener() {
                        @Override
                        public void onErrorResponse(VolleyError error) {
                            String cachedResponse = prefs.getString("json", "");

                            if (!cachedResponse.equals("")) {
                                parseData(cachedResponse);
                            } else {
                                Toast.makeText(MainActivity.this, getString(R.string.network_error), Toast.LENGTH_LONG).show();
                                finish();
                            }
                        }
                    }) {
                        @Override
                        public Map<String, String> getHeaders() throws AuthFailureError {
                            HashMap<String, String> headers = new HashMap<String, String>();
                            headers.put("key", getResources().getString(R.string.api_key));
                            return headers;
                        }
                    };
                    strReq.setShouldCache(false);
                    AppController.getInstance().addToRequestQueue(strReq, Constants.TAG_STRING_REQ);
                }
                else{                       
                    String cachedResponse = prefs.getString("json", "");
                    if (!cachedResponse.equals("")) {
                        parseData(cachedResponse);
                    } else {
                        Toast.makeText(MainActivity.this, getString(R.string.network_error), Toast.LENGTH_LONG).show();
                        finish();
                    }
                }

            } catch (JSONException e) {
                e.printStackTrace();
            }

        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            String cachedResponse = prefs.getString("json", "");
            if (!cachedResponse.equals("")) {
                parseData(cachedResponse);
            } else {
                Toast.makeText(MainActivity.this, getString(R.string.network_error), Toast.LENGTH_LONG).show();
                finish();
            }
        }
    }) {
        @Override
        public Map<String, String> getHeaders() throws AuthFailureError {
            HashMap<String, String> headers = new HashMap<String, String>();
            headers.put("key",getResources().getString(R.string.api_key));
            return headers;
        }
    }; 
    strReqUpdate.setShouldCache(false);
    AppController.getInstance().addToRequestQueue(strReqUpdate, Constants.TAG_STRING_REQ);

这里正在做的是发出一个请求，以查看我的JSON是否有更新，以及是否有开始获取它的请求（如果未获取兑现的JSON）。这两个请求都发送到带有ssl的heroku服务器，但是只有第二个请求会引发错误。我认为这是一个ssl错误，我什至试图夸大ssl握手，如从各种帖子中看到的那样，但没有任何效果。

隔离的第二个请求是：

         StringRequest strReq = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {                               
                        SharedPreferences.Editor editor = prefs.edit();
                        editor.putString("json", response);                                                                                              
                        editor.putLong("version", version);
                        editor.commit();

                        parseData(response); 
                    }
                }, new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        String cachedResponse = prefs.getString("json", "");

                        if (!cachedResponse.equals("")) {
                            parseData(cachedResponse);
                        } else {
                            Toast.makeText(MainActivity.this, getString(R.string.network_error), Toast.LENGTH_LONG).show();
                            finish();
                        }
                    }
                }) {
                    @Override
                    public Map<String, String> getHeaders() throws AuthFailureError {
                        HashMap<String, String> headers = new HashMap<String, String>();
                        headers.put("key", getResources().getString(R.string.api_key));
                        return headers;
                    }
                };
                strReq.setShouldCache(false);
                AppController.getInstance().addToRequestQueue(strReq, Constants.TAG_STRING_REQ);

日志内容：

javax.net.ssl.SSLHandshakeException：javax.net.ssl.SSLProtocolException：SSL握手中止：ssl = 0x61ff28f0：SSL库失败，通常是协议错误错误：14077410：SSL例程：SSL23_GET_SERVER_HELLO：sslv3警报握手失败（外部/ openssl /ssl/s23_clnt.c:744 0x5df0b6fd：0x00000000）