[plug] mailman list setup problem

[Sol]

I've set up and administered 3 mailman lists in the past. It's been no
problem, just follow the documentation. I have been trying to set up a
fourth, and whilst I've configured it in a way very similar  my other
private list, I can't send mail to it. When I mail the list I get the
following error:
---
This message was created automatically by mail delivery software (Exim).

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

  buddhistcouncil at bswa.org
    unknown local-part "buddhistcouncil" in domain "bswa.org"

---
This doesn't seem like a Mailman problem so much as an exim problem.
I've tried restarting mailman and exim, all to no avail. It just won't
recognize the list name part of the email. How can I get this to work?

nb: the other lists under this domain are working fine.

thanks; sol