"407 Proxy Authentication Required" error during java rest request occationally

Question

I am trying to perform a REST request to one of my client URL to get the response using proxy.Most of the time i am able to get the response using my code.But sometimes when i try to send a request using my code i am receiving "407 Proxy Authentication Required" error.This happens rarely but once i get this error,for every consecutive requests i am getting the same error.But when i use POSTMAN tool from chrome to send the same request that was generated to the same URL ,I will be getting the response.But as soon as i get response from POSTMAN if i try with my code again i start getting the response not only from my local machine but from different machines where i run the code as well.I am very confused regarding the issue and not able to figure out why this strange scenario occurs.Is there something i am missing in my code.Kindly help me out guys.I have given my code below :

Code

public Map<String ,Object> ConnectRestService(MyRequest myRequest, String postURL, String httpProxy,int timeout int httpPort, Map<String ,Object> responseMap)
        throws KeyManagementException, UnrecoverableKeyException, NoSuchAlgorithmException, KeyStoreException, CustomException{

    MyResponse myResponse = new MyResponse();
    Map<String ,Object> responseReturnMap = new HashMap<>();
    String output = "";
    TrustStrategy acceptingTrustStrategy = new TrustStrategy() {

        @Override
        public boolean isTrusted(java.security.cert.X509Certificate[] chain, String authType)
                throws java.security.cert.CertificateException {
            // TODO Auto-generated method stub
            return true;
        }
    };

    SSLContext sslContext = SSLContexts.custom()
            .loadTrustMaterial(null, acceptingTrustStrategy)
            .build();


    SSLConnectionSocketFactory csf = new SSLConnectionSocketFactory(sslContext);
    HttpClient httpClient;
    httpClient = HttpClients.custom().setSSLSocketFactory(csf).setProxy(new HttpHost(httpProxy, httpPort)).build();

    HttpHeaders httpHeaders = new HttpHeaders();
    httpHeaders.add("Content-type", "text/xml");
    httpHeaders.add("Accept", "text/xml");
    httpHeaders.add("access-control-allow-origin", "*");
    httpHeaders.add("content-encoding", "UTF-8");
    HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(httpClient);
    requestFactory.setConnectTimeout(timeout);


    try {
        RestTemplate restTemplate = new RestTemplate(requestFactory);
        HttpEntity<MyRequest> entity = new org.springframework.http.HttpEntity<MyRequest>(
                myRequest, httpHeaders);
        ResponseEntity<String> response = restTemplate.exchange(postURL, HttpMethod.POST, entity, String.class);


    } catch (Exception ex) {
        logger.error(ex.getMessage(), ex);
    }

    return responseReturnMap;
}

Kindly help me out figuring out what i am missing here.

Answer 1

In case of a 407 error, the response that you are receiving must contain a special Proxy-Authenticate header. This header will tell you what kind of authentication the proxy server is expecting.

What you need to do is include a Proxy-Authorization header in your request. The typical syntax for a Proxy-Authorization header is Proxy-Authorization:<type-of-authentication-scheme> <credentials-for-authentication-at-proxy-server>.

Proxy-Authenticate header will let you know the type of authentication scheme that you need to use.