JIRA Creating Bug using Rest Assured API's : AuthenticationException: Invalid Username or Password

Query :

Creating Bug in JIRA portal automatically when the Test gets failed using Rest assured API(java) but the output is AuthenticationException: Invalid Username or Password but the Same Getting successful in Postman. I can able to create Bug and use all the APIs of Jira which works fine by basic username and password authentication itself.Have tried a couple of scenarios that I found in StackOverflow but the same response (AuthenticationException: Invalid Username or Password )

Steps Taken :

Scenario 1 : 
------------

public void endTest(ITestResult result) throws JiraException {
        System.out.println("Ended Test execution");
        String username = "*******";
        String password = "*******";

        if (result.getStatus() == ITestResult.FAILURE) {
            BasicCredentials cred = new BasicCredentials(username, password);
            JiraClient jira = new JiraClient("http://localhost:8080/", cred);
            Issue issueName = jira.createIssue("AAA", "Bug").field(Field.SUMMARY, result.getMethod().getMethodName() + "is failed due to: " + result.getThrowable().toString()).field(Field.DESCRIPTION, "Please take this Bug priority").execute();
            System.out.println("Issue created in Jira with key : " + issueName.getKey());
        }

    }

Response : net.rcarz.jiraclient.JiraException: Failed to retrieve issue metadata
401 Unauthorized: {"servlet":"Stapler","message":"Invalid password/token for user: *******","url":"/rest/api/latest/issue/createmeta","status":"401"}

Scenario 2 : 
------------

public static String invokePostMethod() throws ClientHandlerException, AuthenticationException, IOException {
        String username = "*******";
        String password = "*******";
        Client client = Client.create();
        WebResource webResource = client.resource("http://localhost:8080/rest/api/2/issue");

        String data = "{\n" +
                "    \"fields\": {\n" +
                "        \"project\": {\n" +
                "           \"key\":\"QQQ\"\n" +
                "        },\n" +
                "        \"summary\": \"creating Bug QQQ project\",\n" +
                "         \"description\": \"Exception three\",\n" +
                "        \"issuetype\": {\n" +
                "            \"name\":\"Bug\"\n" +
                "        }\n" +
                "    }\n" +
                "}";

        String auth = new String(Base64.encode(username + ":" + password));
        ClientResponse response = webResource.header("Authorization", "Basic " + auth).type("application/json").accept("application/json").post(ClientResponse.class, data);
        int statusCode = response.getStatus();

        if (statusCode == 401) {
            throw new AuthenticationException("Invalid Username or Password");
        } else if (statusCode == 403) {
            throw new AuthenticationException("Forbidden");
        } else if (statusCode == 200 || statusCode == 201) {
            System.out.println("Ticket Create succesfully");
        } else {
            System.out.print("Http Error : " + statusCode);
        }
        // ******************************Getting Responce body*********************************************
        BufferedReader inputStream = new BufferedReader(new InputStreamReader(response.getEntityInputStream()));
        String line = null;
        while ((line = inputStream.readLine()) != null) {
            System.out.println(line);

        }
        return response.getEntity(String.class);
    }

Response: Exception caught - Invalid Username or Password