Getting authorized erro when made ajax request

$(function () {
       $.ajax({
           type:"GET",
           headers: {
               'Authorization':'Basic ' + btoa("XXXXX"+ ':')
           },
           dataType:"json",
           contentType: "application/javascript",
           async: true,
           crossDomain: true,

           url: "https://www.streak.com/api/v1/pipelines",
           success: GetStages1,
           error: GetError
       });

   });

   function GetStages1() {
       alert("call");
   }
function GetError() {
       alert("Error");
   }