We are performing a major software upgrade on our mail servers on the evening of Wednesday May 4th, starting from 6pm UK time and lasting for 2-3 hours. The Smartmessages web interface will remain available, but no mailshots will be sent during the maintenance window.
Update: I'm sorry to report that our software upgrades were curtailed by a major hardware failure last night. We're working on a fix.
Update: We've now provisioned new servers to take over the failed servers and all services are now running normally. Many apologies for the delay to today's sends.