I'm getting the following errors returned when users attempt to subscribe to
one of our internal mailing lists.  Any help with an interpretation would be
appreciated...

Serious error occurred - traceback follows
------------------------------------------
>>> Error X'00980009' sending mail message (LSWMAIxx) <<<
 -> Severity: Warning
 -> Facility: Mail routines (LSWMBX/LSWMAIL)
 -> Abstract: No primary recipient left