Image donot uploaded with AjaxFileUpload in folder in server

Use the example in my page, but it did not work after post it on the web server with WS2008, IIS 7.5, and use VS2015.

"Multiple files upload with Drag and Drop and Progress bar using ASP.Net AJAX AjaxFileUpload control"

<ajaxToolkit:AjaxFileUpload ID="AjaxFileUpload1" runat="server" MaximumNumberOfFiles="15"
CssClass="tkFup" OnUploadComplete="OnUploadComplete" ThrobberID="MyThrobber"
AllowedFileTypes="jpg,jpeg,png,gif" BackColor="#ffffc4" />

protected void OnUploadComplete(object sender, AjaxFileUploadEventArgs e)
{      
   string fileName = Path.GetFileName(e.FileName);
   AjaxFileUpload1.SaveAs(Server.MapPath("~/Uploads/" + fileName));          
}