> Also noticed that I got several ok'ed messages from the server with the
> following errors:
>
> An error occurred while processing file 97353 from
> [log in to unmask]:
> "Mail message sent to the LISTSERV address contains invalid RFC822 fields
> and
> could not be parsed successfully".
>
> RFC822 parser messages follow:
>
> <W> MESSAGE-ID field duplicated. Last occurrence was retained.
>
> I have seen this error before, and have not been able to determine what is
> causing it?
It means that there are two Message-ID headers in the message.
Message-ID is used to provide a unique identification code for a
message, so that it can be referenced by other messages. LISTSERV
complains even when the two message-ids are identical (as usually seems
to be the case when I see it).