Rackspace is now beginning rolling reboots of Cloud instances throughout the ORD datacenter, where a majority of Mailgun infrastructure resides. We planned to fail over to our alternate location to minimize impact, however, we have been unable to do so. As a result, you may see connectivity issues to Mailgun's API and SMTP endpoints. We have all hands on deck to recover services immediately. We are truly sorry for the inconvenience this will cause. Please reach out to us if we can help in any way.