I've been having the same problem today with my CB login. If I load the site with the www. prefix, it logs in fine. If I forego the www, it doesn't log in at all, no error message, just reloads. I checked the configuration file and live_site is blank. I've had a glitch for a while now that might be related where when you login there seems to be a cookie issue and the site doesn't realize you've logged in until you force a refresh of the page or navigate to another page.
Any other suggestions?
Site is
www.slacklink.org