I am getting an error message when doing ping for Yahoo

Here is what I have for yahoo Ping url

Yahoo! => http://search.yahooapis.com/SiteExpl...ing?sitemap=%s



here is the error message

http://search.yahooapis.com/SiteExpl...temapindex.xml

cURL Error: Error http_code "403" reading "http://search.yahooapis.com/SiteExplorerService/V1/ping?sitemap=http%3A%2F%2Fgpakistan.com%2Fsitemapindex.xml"

thanks