Because our mail server was sending large amounts of spam, we have temporarily turned off the SMTP portion of the system while we identify, isolate, and correct the problem. As a result, outgoing mail is disabled. Users are able to receive mail. Users can also create draft messages but these must be manually sent after the SMTP server is re-enabled.
Update 9:07am, April 3, 2009:
Outgoing mail is re-enabled. Downtime was approximately 10 minutes.