[support] Strange access denied Error

I have a Drupal 6.26 site on a VPS. At random, pages return WSOD and no log in Apache. Whenever this happens I see an access denied error in the log from user Anonymous and the URL I just tried and the time etc. The hostname there is the IP of the server itself. That's what's bizarre. Also that it's anonymous. I am logged in as user #1. I can't find any report of this issue. Anyone ever see such a thing? Thanks, Fred