The mail is forwarded, but no vacation response is sent, and the mail is
not forwarded. I find the lda error like this:
_discarding_vacation_response_for_implicitly_delivered_message;
_no_known_(envelope)_recipient_address_found_in_message_headers_
(recipient=<bob.mil...@hostname.domain.tld>,_and_no_additional_
`:addresses'_are_specified)
Does the message have To: and From: headers? I recall getting the same
(or similar) output when those headers were missing during my testing.
Adding them fixed the issue.
