The site experienced an outage yesterday, June 17, 2015 from approximately 6:00 PM to 10:00 PM.
I immediately got in touch with the hosting service as well as several other services we used and found out the error was caused by a hardware failure in one of the proxy nodes of our proxy servers. Here is the message from the host.
at first we had the network maintenance you were norified (sic) about yesterday, but around the same time the proxy node that your account is on was overheating and it took us a while until we noticed that the issue wasn’t actually related to the maintenance. Then an on-site tech had to pull the server out of the rack until it cooled down, because it didn’t boot anymore. After a while we were able to rack and boot it again and adjusted the fan settings to make sure it can’t overheat again. I apologize about the inconvenience.
All issues are now resolved and the site is back online. Thank you for your patience.