We identified a problem with the DNS resolver at our infrastructure provider. The effect of the issue was that we were unable to do DNS lookups during the outage. We suspended delivery of all e-mails, imports and exports to be queued until the problem was amended.
You may have experience degraded performance using the administrative interface, signup forms and API as well.
Our infrastructure provider fixed the problems as of 15:00 and all services are now back to normal operations.