The following error message accompanies an LSMTP message stating Receive
error : unknown error.

The enclosed message, found in the xxx mailbox and shown under the  spool ID
24738 in  the  system log,  has  been identified  as a  possible delivery
error  notice for the following  reason: mail origin is  listed in the
"Filter="   list   header    keyword   (or   its   default    value   for
the
xxx list).