Instead of trying to do
Response.Clear() / ClearContent() / ClearHeaders(), like many web solutions show you - but don't work !
Just go to the aspx page that was created by the wizard (not the code-behind .cs page), delete everything except for the first directive tag telling the server to parse the page in the aspx engine :
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ajax.aspx.cs" Inherits="Appcident.ajax" %>
and in your code behind, just return a response, like: