I want to use RestTemplate for my API call. I am trying to initialize a payment gateway but it always returning an error message that says java.net.HttpRetryException: cannot retry due to server authentication, in streaming mode. I really need help on how to resolve it.It was actually working when I was passing the values direct without having to reference it from somewhere. This is what I did.

@Component
    public class RestTemplateService {
        private RestTemplate restTemplate;

        @Autowired
        public RestTemplateService(RestTemplateBuilder restTemplateBuilder) {
            this.restTemplate = restTemplateBuilder
                    .errorHandler(new RestTemplateResponseErrorHandler())
                    .build();
        }

        public <T> ResponseEntity<CustomPaymentResponse> post(String url, T req, HttpHeaders headers) {

            HttpEntity entity = headers == null ? new HttpEntity(req) : new HttpEntity(req, headers);
            ResponseEntity<CustomPaymentResponse> response = restTemplate.exchange(url, HttpMethod.POST, entity, CustomPaymentResponse.class);
            return response;
        }

        public ResponseEntity<CustomPaymentResponse> get(String url, HttpHeaders headers) {
            HttpEntity entity = headers == null ? null : new HttpEntity(headers);
            ResponseEntity<CustomPaymentResponse> response = restTemplate.exchange(url, HttpMethod.GET, entity, CustomPaymentResponse.class);

            return response;
        }

        public ResponseEntity<CreatePlanResponse> delete(String url, HttpHeaders headers) {
            HttpEntity entity = headers == null ? null : new HttpEntity(headers);
            ResponseEntity<CreatePlanResponse> response = restTemplate.exchange(url, HttpMethod.DELETE, entity, CreatePlanResponse.class);

            return response;
        }
    }

public class RestTemplateResponseErrorHandler implements ResponseErrorHandler {
        @Override
        public boolean hasError(ClientHttpResponse httpResponse) throws IOException {
            HttpStatus statusCode = (HttpStatus) httpResponse.getStatusCode();
            return (statusCode.is4xxClientError() || statusCode.is5xxServerError());
        }


        @Override
        public void handleError(ClientHttpResponse httpResponse) throws IOException {
            HttpStatus statusCode = (HttpStatus) httpResponse.getStatusCode();

            if (statusCode.is5xxServerError()) {
                // handle SERVER_ERROR
            } else if (statusCode.is4xxClientError()) {
                // handle CLIENT_ERROR
                if (statusCode == HttpStatus.NOT_FOUND) {
                    try {
                        throw new ChangeSetPersister.NotFoundException();
                    } catch (ChangeSetPersister.NotFoundException e) {
                        throw new RuntimeException(e);
                    }
                }
            }
        }

    }

@Service
@RequiredArgsConstructor
public class UserPayStackPaymentServiceImpl implements UserPayStackPaymentService{

    @Value("${payStackSecretKey}")
    private String payStackSecretKey;
    private final RestTemplateService restTemplate;
    private final UserPayStackPaymentRepository userPayStackPaymentRepository;
    private final SaleRepository saleRepository;
    @Override
    public ResponseEntity<CustomPaymentResponse> initializePayment(Long orderId) {

        Map<String, String> request = new HashMap<>();
        Optional<SaleEntity> order = saleRepository.findById(orderId);

        double amountToBePaid = order.get().getTotalPrice() * 100;

        request.put("email", order.get().getBuyer().getEmail());
        request.put("amount", String.valueOf(amountToBePaid));

        ResponseEntity<CustomPaymentResponse> response = restTemplate.post(PAYSTACK_INITIALIZE_PAY, request, PaymentConstants.headers());
        System.out.println("The initialize payment response is "+response.getBody().toString());
        if (response.getStatusCode() == HttpStatus.OK) {
            System.out.println("The response is ok in this place "+response.getBody().getData().toString());
            ObjectMapper objectMapper = new ObjectMapper();
            Map<String, Object> mapResponse = objectMapper.convertValue(response.getBody().getData(), Map.class);

            UserPaymentStack userPaymentStack = UserPaymentStack.builder()
                    .user(order.get().getBuyer())
                    .amount(order.get().getTotalPrice())
                    .status(PaymentStatus.PENDING.name())
                    .order(order.get())
                    .reference((String) mapResponse.get("reference"))
                    .accessCode((String) mapResponse.get("access_code"))
                    .build();
            userPayStackPaymentRepository.save(userPaymentStack);

            return ResponseEntity.ok( CustomPaymentResponse.builder()
                    .message(response.getBody().getMessage())
                    .status(true)
                    .data(mapResponse)
                    .build());
        }
        System.out.println("Response is not ok in this place "+response.getBody().getMessage());
        return ResponseEntity.badRequest().body(new  CustomPaymentResponse(false,response.getBody().getMessage(),null));
    }

}