Sometime for debugging or traversing large data in EP causing an issue of timeout, we can increase the timeout by setting the AsyncPostBackTimeout for AJAX which was causing the timeout. Here is the code which we can write in Page_Load event:

protected void Page_Load(object sender, EventArgs e)
{
    ScriptManager scripts = ScriptManager.GetCurrent(this.Page);

   if (scripts != null)
    {
        scripts.AsyncPostBackTimeout = 800; // 800 seconds
    }
}