It is common to have Apache as your static web server to serve images/css/js files and use modules such as mod_rewrite or mod_jk to route to your dynamic contex

It is common to have Apache as your static web server to serve images/css/js files and use modules such as mod_rewrite or mod_jk to route to your dynamic context. It seems like his dynamic content server is down (could be the jetty server he was referring to), hence the 503 error code.