Authenticate SICF service using SAPUI5 json model

Dear Experts,

I have developed an SAPUI5 app and I am trying to fetch data from SAP using the SICF service which returns JSON format. I am not using and OData services.

When I am trying to authenticate this service using JSONModel I am getting unauthorized error. I am passing the right credentials but still facing the same issue.

Sample Code....

var userName = "USERNAME";

  var password = "PASSWORD";

  var credentials = userName + ':' + password;

  var hash = btoa(credentials);

  var auth = 'Basic '+hash;

var header = {

         'Authorization':auth,

         'Access-Control-Allow-Origin':'*',

         'Content-Type':'application/json'

     }

  var customerModel = new sap.ui.model.json.JSONModel();

  customerModel.loadData("http://hostname:port/ui5?&mobile=123456789",null,true,'GET',false,false,header);

I am getting below error....

Response for preflight has invalid HTTP status code 401

Kindly help...!

Thanks

Ravi