凌空：[2526] BasicNetwork.performRequest：意外的响应代码503

Question

我在使用排球库发出网络请求时遇到此错误，该应用程序正常运行，但是过一会儿我收到此错误，当我使用邮递员发送相同的请求时成功

E/RecyclerView: No adapter attached; skipping layout
E/Volley: [2526] BasicNetwork.performRequest: Unexpected response code 503 for https://www.mangaeden.com/api/list/0/
W/System.err: com.android.volley.ServerError
W/System.err:     at com.android.volley.toolbox.BasicNetwork.performRequest(BasicNetwork.java:205)
        at com.android.volley.NetworkDispatcher.processRequest(NetworkDispatcher.java:131)
        at com.android.volley.NetworkDispatcher.processRequest(NetworkDispatcher.java:111)
        at com.android.volley.NetworkDispatcher.run(NetworkDispatcher.java:90)
I/.toshokan_mang: Waiting for a blocking GC ProfileSaver

我的功能

private void parseJson(){
        final String JSON_URL = "https://www.mangaeden.com/api/list/0/";
        requestQueue = Volley.newRequestQueue(getActivity());

        JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, JSON_URL, null,
                new Response.Listener<JSONObject>() {
                    @Override
                    public void onResponse(JSONObject response) {
                        try {
                            JSONArray jsonArray = response.getJSONArray("manga");
                            for (int i=0; i<response.length(); i++){
                                JSONObject mg = jsonArray.getJSONObject(i);
                                Manga manga = new Manga();
                                manga.setMangaName(mg.getString("t"));
                                manga.setBackground(mg.getString("im"));
                                mangas.add(manga);
                            }

                            CustomAdapter adapter = new CustomAdapter(getContext(),mangas);
                            recyclerView.setAdapter(adapter);
                            adapter.setOnMangaClickListener(MangaListFragment.this);

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

                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
            }
        });
        request.setShouldCache(false);
        requestQueue.add(request);
    }

我应该怎么做才能解决这个问题？