We’ve been seeing some very high sending volume recently. And this is supposed to be the slow summer period. We seem to have a lot more users (we just hit 375,000) who are sending a lot more emails (we’re sending between 25-28 million a day now). To avoid ISP throttling from all this increased volume, we’re making some adjustments to our delivery servers. This is why some of our customers are experiencing delays in receiving their test messages. We’ve got an idea for a fix, and should be implementing that soon. To complicate things slightly more, one of our MTAs had some problems last night. Our data center worked hard to repair the RAID, but it ultimately did not help. We’re re-routing the mail queue from that data center to another, and we expect things to get back to normal within a few hours. Sorry for the inconvenience. We’re working hard to fix it.
Update: As of 11:44am ET, all of the unsent payloads from the broken server, which equated to about half a million emails, were loaded up to a different server for delivery. Also, an update that was meant to address the slow test delivery issue mentioned above was actually made live yesterday. However, any noticeable improvements from that update would’ve been offset by that server problem. As soon as this queue is caught up, we should start seeing test campaign improvements. On the plus side, this gives us an opportunity to upgrade one of our servers. Like spinning plates, I tell ya. Big, complicated, expensive plates.