I got that message on Campbx, too.  If you try to login or reload a page a few times after getting that error, the page seems to load.  It literally would take 3-4 reloads until the page came up rather than giving me the error. I liked Campbx so far, but I moved most of my btc out of it for now until this issue is resolved.  Transferring took 3-4 tries as well.

Edit: It now seems that there is a message saying the site will be back up in 15 minutes.