I use the site lookup tool on this site almost everyday since we block Uncategorized by default (most malware hosts are uncategorized according to our malware reverse-engineer). Lately I have noticed it is either slow or non-responsive. The last week I have been getting "Invalid HTTP response" when submitting a URL or a category suggestion. According to Websense article http://www.websense.com/content/support/library/web/v75/wcg_help/HTML.aspx this is due to a 502 error where the web server does not respond correctly.
Anybody else seeing this? Hopefully this may bring it to somebody's attention. :)