How to add Tester into TestFlight through ITunesConnect REST APIs?

Question

I am working on a project to automate the adding/removing of users into ITunesConnect - TestFlight for one of my app in appstore.

I used the following commands to add/remove tester for my app successfully using the fastlane pilot tool (https://docs.fastlane.tools/actions/pilot/).

bundle exec fastlane pilot add [email protected] -a com.abc.MyApp
bundle exec fastlane pilot remove [email protected] -a com.abc.MyApp

I would like do the same using a UI whose backend is in Java. I found the REST end points in this below links

https://github.com/fastlane/itc-api-docs/ https://github.com/fastlane/itc-api-docs#register-new-external-beta-tester

But the code I wrote is not working properly and unable to add tester into TestFlight.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;

import org.apache.http.auth.AuthenticationException;
import org.apache.http.auth.Credentials;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.config.CookieSpecs;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.auth.BasicScheme;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;

public class TestFlightCreateTester {

    public static void main(String[] args) throws AuthenticationException, ClientProtocolException, IOException {

        RequestConfig customizedRequestConfig = RequestConfig.custom().setCookieSpec(CookieSpecs.IGNORE_COOKIES).build();
        HttpClientBuilder customizedClientBuilder = HttpClients.custom().setDefaultRequestConfig(customizedRequestConfig);
        CloseableHttpClient client = customizedClientBuilder.build(); 
        HttpPost httpPost = new HttpPost("https://itunesconnect.apple.com/WebObjects/iTunesConnect.woa/ra/users/pre/create");
        UsernamePasswordCredentials creds = new UsernamePasswordCredentials("testUserName", "testPassword");
        httpPost.addHeader(new BasicScheme().authenticate((Credentials) creds, httpPost,null));

        String json = "{\"testers\":[{\"emailAddress\":{\"value\":\"[email protected]\",\"errorKeys\":[]},\"firstName\":{\"value\":\"Hareesh\"},\"lastName\":{\"value\":\"Sarma\"},\"testing\":{\"value\":true},\"groups\":[]}]}";
        StringEntity entity = new StringEntity(json);
        httpPost.setEntity(entity);
        httpPost.setHeader("Accept", "application/json");
        httpPost.setHeader("Content-type", "application/json");

        CloseableHttpResponse response = client.execute(httpPost);

        BufferedReader r = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

        StringBuilder total = new StringBuilder();

        String line = null;

        while ((line = r.readLine()) != null) {
           total.append(line);
        }
        System.out.println(total.toString());
        response.close();
    }

}

I get the following response when I run the above code

UnauthenticatedRequest ID: XXXXXXXXXXXXXXXX.0.0