There was a problem while notifying Google.

XML file is being generated without any problems. But i still get the error message in red “There was a problem while notifying Google.” When i click “result”, i can see what the plugin is trying to ping to google:
Trying to ping: http://www.google.com/webmasters/sitemaps/ping?sitemap=http%3A%2F%2Flocalhost%2Fmolitor%2Fsitemap.xml.
Obviously “localhost…” is wrong and outdated. Where does that come from? Because i replaced all localhost strings in my DB after moving to live server. And of course i also changed siteurl and homeurl.