[Samba] Invalid request received from you

[L-Soft list server at The University of Nebraska at Lincoln (1.8e)]

Your message is being returned to  you unprocessed because no command was found
in the  message body.  LISTSERV expects  commands in the  body of  the message,
rather than in the message subject, because some users have no control over the
contents of the "Subject:" field on outgoing messages.