android - NTLM Authentication with OkHttpClient for Android

Question

I am trying to add NTLM authentication (username and password) to a Retrofit OkHttp client.

import java.io.IOException;

import okhttp3.Credentials;

import okhttp3.Interceptor;

import okhttp3.Request;

import okhttp3.Response;


public class NTMLAuthInterceptor implements Interceptor {

    private String credentials;

    public NTMLAuthInterceptor(String user, String password) {
        this.credentials = Credentials.basic(user, password);
    }

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();
        Request authenticatedRequest = request.newBuilder()
            .header("Authorization", credentials).build();
        return chain.proceed(authenticatedRequest);
    }
}

Adding the interceptor to an OkHttp client

   OkHttpClient client = new OkHttpClient.Builder()

    .addInterceptor(new NTMLAuthInterceptor(username, password))

    .build();

but in response I am getting 401 error. Can anyone help me?