OK I've gotten mailman to let me create a list (sullivanfamily) and it sends me a notification that the list was created, but when I try to subscribe to the list and it sends me a confirmation email that I should reply to I reply and get the error "Error while performing operation: RCPT TO <sullivanfamily-request@xxxxxxxxxxxxxxxx> failed; <sullivanfamily-request@xxxxxxxxxxxxxxxx>...User Unknown" How do I fix this?
