未在ajax调用上加载的PHP文件（AWS服务器）

The following error is being thrown in the browser console while ajax calls are made in the AWS server

XMLHttpRequest cannot load http://<awsdns>/folder/webpage.php. 
Origin http://awsdns is not allowed by Access-Control-Allow-Origin.

Here is how ajax call is being made

    $.ajax({
        type    : 'POST',
        url     : gbWebroot+'folder/webpage.php',
        data    : postFormData,
        dataType: 'json',
        encode  : true,
        success     : function(data) {

        }
    });

Any idea why this error is being thrown?