Zendesk has been down today, off and on. We have been told by Zendesk Support that they are attempting to bring services back up as quickly as possible. There will be delays in our support tickets being replied to as we play catch-up, but we will get to them ASAP!!!
UPDATE (2:21 PM) : Zendesk has confirmed that they are receiving a DDoS attack. We will update once we have more information.