We are currently investigating an issue on one of our pop3 hosting servers. It appears to be a complex issue affecting a number of accounts. We believe we are near bringing this component back to full functionality.
Symptom: Cluster is up and responsive but certain users are not receiving mail. (related to a corrupted journal on one of the SANs)
11 AM EST: Service restored. We are still researching the issue and will provide an update after the weekly maintenance this Saturday. This appears to have been caused by a DDoS that did not get properly picked up.