如何处理ajax跨域访问报错501的问题？

$.ajax({
   type: "POST",
  url: "http://192.168.1.202/sensordata.php",

  contentType:'application/json; charset=utf-8',
  data: JSON.stringify(ajaxPostData),
  dataType:'json',
  success: function(data){
   //On ajax success do this
   console.info("success.");
   if (data["status"] == "ok"){
    alert("Settings is Ok. The Machine is rebooting.");
   }
  },
  error: function(xhr, ajaxOptions, thrownError) {
   //On error do this
   console.info("error.");
   if (xhr.status == 200) {

    alert(ajaxOptions);
   }
   else {
    alert(xhr.status);
    alert(thrownError);
   }
  }
 });