Android Volley AuthFailureError

Question

I'm trying to make the following request in Volley:

The request is being called twice, and I get a 401 error, which is the server authentication error, like if the token was invalid (I already checked and the token is valid):

I've tried:

• Making a JsonRequest, with either JsonObjectRequest and JsonArrayRequest, both give the same error.
• Tried with accept and content type, and also without those headers, getting same error.
• And the last try is with the following code, a StringRequest, with Content-Type header:

public void getUserFriends(final API.OnAPIResponse listener) {
    FriendsRequest request = FriendsRequest.newInstance(listener);
    //added this to see if it stopped being called twice
    request.setRetryPolicy(new DefaultRetryPolicy(0, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
    VolleySingleton.getInstance().addToRequestQueue(request);
}
private static class FriendsRequest extends StringRequest {
    public static FriendsRequest newInstance(final API.OnAPIResponse listener) {
        String serviceURL = API.API_URL + FRIENDS_PATH;
        return new FriendsRequest(Request.Method.GET, serviceURL, new Response.Listener < String > () {
            @Override
            public void onResponse(String response) {
                APIResponse apiResponse = null;
                if (listener != null) {
                    listener.onResponse(apiResponse);
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
                APIResponse apiResponse = getErrorResponse(error);
                if (listener != null) {
                    listener.onResponse(apiResponse);
                }
            }
        });
    }
    public FriendsRequest(int method, String url, Response.Listener < String > listener, Response.ErrorListener errorListener) {
        super(method, url, listener, errorListener);
    }
    public FriendsRequest(String url, Response.Listener < String > listener, Response.ErrorListener errorListener) {
        super(url, listener, errorListener);
    }
    @Override
    public Map < String, String > getHeaders() throws AuthFailureError {
        HashMap < String, String > headers = new API().getTokenHeader();
        headers.put("Content-Type", "application/json; charset=utf-8");
        Log.d("Network", headers.toString());
        return headers;
    }
}

I did manage to make a request to that API, that doesn't require the token header.

UPDATE: I'm still trying; using EasyVolley, I'm getting the same error:

EasyVolley.withGlobalQueue()
        .load(API_URL + FRIENDS_PATH)
        .addHeader("token", TokenGenerator.getToken())
        .addHeader("Content-Type", "application/json; charset=utf-8")
        .asJsonObject()
        .setSubscriber(mainActivity)
        .setCallback(new ASFRequestListener<JsonObject>() {
            @Override
            public void onSuccess(JsonObject response) {
                Log.d("response", response.toString());
            }

            @Override
            public void onFailure(Exception e) {
                e.printStackTrace();
            }
        })
        .start();

Getting same error, but at least it's called once:

UPDATE: tested with OkHttp, don't know what else to try, I've checked multiple times, the token works in the RESTClient.

OkHttpClient client = new OkHttpClient();

    okhttp3.Request request = new
            okhttp3.Request.Builder()
            .header("token", TokenGenerator.getToken())
            .url(API_URL + FRIENDS_PATH)
            .build();
    // Get a handler that can be used to post to the main thread
    client.newCall(request).enqueue(new Callback() {
        @Override
        public void onFailure(Call call, IOException e) {
            e.printStackTrace();
        }

        @Override
        public void onResponse(Call call, final okhttp3.Response response) throws IOException {
            response.headers();
            if (!response.isSuccessful()) {
                throw new IOException("Unexpected code " + response);
            }
        }
    });