ok that's an server error, i can only tell you why you recive that msg, possibly the runescape/jagex server was down or the browser was unable to communicate properly well. browser sends signal to the particular website which you have just typed, it tries to connect it multiple times before you get this msg, this msg means your browser/chrome was unable to communicate with jagex/rs server correctly and didn't received the proper response resulting chorome saying oops!!
