Issue in POST method with Woocommerce REST API

Question

I'm developing an android app with Woocommerce REST API. I 'm able to access the data's through this REST api using GET method,

now i'm facing issue in creating new customer using this REST API.

here POST method is not working.

my END_POINT is "http:example.com/wp-json/wc/v1/customers"

the problem is am getting authentication error.

I'm using OkHttp for network call.

Here is my code:

protected String doInBackground(Void... params) {
        try {
            MediaType JSON = MediaType.parse("application/json; charset=utf-8");
            String authHeader = Credentials.basic(Config.CONSUMER_KEY, Config.CONSUMER_SECRET);
            Log.e(TAG, "doInBackground: auth -> " + authHeader);
            RequestBody body = RequestBody.create(JSON, json);

            Request request = new Request.Builder()
                    .url(url)
                    .post(body)
                    .addHeader("Content-Type", "application/json; charset=utf-8")
                    .addHeader("Accept", "application/json")
                    .addHeader("Authorization", authHeader)
                    .build();

            OkHttpOAuthConsumer consumer = new OkHttpOAuthConsumer(Config.CONSUMER_KEY, Config.CONSUMER_SECRET);

            OkHttpClient client = new OkHttpClient.Builder()
                    .addInterceptor(new SigningInterceptor(consumer))
                    .build();

            Response response = client.newCall(request).execute();

            return response.message();
        } catch (IOException e) {
            e.printStackTrace();
            Log.e(TAG, "doInBackground: " + e.getLocalizedMessage());
            return Tag.IO_EXCEPTION;
        }
    }

Response message is :

{"code":"woocommerce_rest_cannot_create","message":"Sorry, you are not allowed to create resources.","data":{"status":401}}

i don't know where is an issue is.

If anyone experienced this problem, means please share your solution.

Thanks in advance.