Yesterday's problems with MIAD email were caused by a user account being compromised due to a very weak password. Over 10,000 messages were being held in queue on the system. Because the vast majority of this queue was outbound spam it was deemed necessary to flush and delete these messages so as to get email service back up and running as soon as possible.
Sadly, some email messages may have been lost during this process. If you sent or were hoping to receive email between 9am-1pm yesterday it's possible those messages are gone. We apologize for any inconvenience this may have caused.