some times this happen, at the time when google bot visit your site may be down or there are some meters on the hosting side, for page and bandwidth use per ip. wait for some time and bot will get them up soon.
Hi folks, Yes, I've searched for 2 days and no relief. Brought a small site online month ago. Verified in google. Code validates strict as well. Header check OK (http://oyoy.eu/page/headers). No sitemap yet, but it's a very small and simple site. On 8/12, google wouldn't index - said it detected an authentication error. Acc to webmaster tools, last google update was 8/27. It appears google has tried to crawl several times. Google won't index the site. There is no logon for this website. It's a small informational site called www.thebrainevent.com. The htaccess and robot files are like the other sites I've created and have never had this problem. Nowhere on the internet does it say what I can DO to fix this. I hunted! The code is small and clean. I don't know what to do. PLEASE advise! Thanks a million.
this might be helpful for you: http://www.google.com/support/forum/p/Webmasters/thread?tid=6bb12f9d43abd469&hl=en