Is it RFC compliant for a mail server to respond with a 5xx message after the DATA command has been completed? I am trying to find why a subscriber to one of the lists on my server was getting deleted even though I did not get any non-delivery reports from my mail server. When I connected with telnet to do a manual session with the affected server, I got this far:

250 - <Welcome message>
helo <my mail server hostname>
250 - <mail server hostname> - <my mail server hostname>
mail from: "My name" <my address>
250 OK
rcpt to: "User's name" <User's address>
250 OK
DATA
354 Send data message
Test message text.
.
561 No RFC822 Headers
quit

Is this mail server broken?

andrew