> from [log in to unmask] to [log in to unmask]

John,

Since there is no subscriber on your list with any of the
"words" in that troublesome first address above, just email to
[log in to unmask] and ask him under what address is he
subscribed to your list (or from whom is he receiving "bounces"
of postings to your list).

If he's really at that new address, he'll likely respond and you
can fix the problem subcription.

Peter