"An existing connection was forcibly closed by the remote host" during DATA
reads the same whether the server refused the SIZE, hit an hourly quota, or
simply dropped the socket — and only the first is something an operator can act
on. The message now carries host:port, the encryption in use and the total
attachment size, so the size can be ruled in or out without a second attempt.
A path that does not exist is not counted: the mail library skips it, so
reporting it would describe a message that was never sent.
