My guess:

1) recipient's ISP is not accepting a "null" RFC821 MAIL FROM:<> contrary
to RFCs

2) it's hard to say if the ISP is "eating" the output.

Editorial Comment: perhaps the user instead should be losing patience
with his/her ISP instead!  E.g., I regularly advise certain ISP customers
to switch to a more reliable provider or to ask them to fix their
anti-spam a/v software config.

/Pete

At 16:24 09/03/2003 Wednesday, David Rubin wrote:
 >For some addresses, information mails from Listserv do not reach the sender.
 >
 >Those same addresses have no problem receiving normal mail from
Listserv, such as list postings and DISTRIBUTE jobs.
 >
 >For example, issuing a REVIEW command results in one message from Listserv
 >confirming the command, but no subsequent message containing the LIST file.
 >
 >This only happens with certain ISPs, so I suspect Listserv or LSMTP is
creating
 >a message that is incorrectly rejected by the ISP. However, I see no
 >evidence of
 >this in the log files; it appears that the mail is delivered.