Unauthorized 401 - Spring Boot service - spring-boot

Question

I have a spring boot service calling another spring boot service.
Both services deployed into docker container.
And when the first service calling the second service, the second service got 401 response. While when i do the same request using PostMan I got a valid response.
Given I am using the credential through postman and the service itself.
Any Idea why this may happen? Is there any related to docker deployment ?
Code used to call the second service
try {
urlStr = licenseRequest.getString(LicenseRequest.URL);
logger.info("URL: "+ urlStr);
URL url = new URL(urlStr);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("POST");
con.setRequestProperty("Content-Type", "application/json");
// auth
String authStrEncoded = Base64Utils.encodeToString((username + ":" + password).getBytes());
con.setRequestProperty("Authorization", "Basic " + authStrEncoded);
if (!licenseRequest.isNull(LicenseRequest.BODY))
{
String body = licenseRequest.getString(LicenseRequest.BODY);
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream (
con.getOutputStream());
wr.write(body.getBytes());
wr.close();
}
//Get Response
InputStream is = con.getInputStream();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
StringBuilder response = new StringBuilder(); // or StringBuffer if Java version 5+
String line;
while ((line = rd.readLine()) != null) {
response.append(line);
response.append('\r');
}
rd.close();
return response.toString();
}