At my site students.scisdragons.net I recently put in WP Super Cache. It seems to be working ok, except that occasionally I get in Chrome:
Server error The website encountered an error while retrieving http://students.scisdragons.net/wp-admin/network/sites.php. It may be down for maintenance or configured incorrectly. Here are some suggestions: Reload this webpage later. HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.
I refresh the screen, and it's gone. I don't see anything in the apache error log. What should I be looking for. I'm using Ubuntu Server and Apache 2.