relay_transport is not for smarthosts. It is for domains that match
$relay_domains, i.e. the relay class.
> Or FWIW, either or both of:
> default_transport = lmtp:mail.example.com
> relay_transport = lmtp:mail.example.com
> depending on whether the messages to delivered via LMTP are just the
> inbound traffic, or truly "all mail", even bounces to the original
> sender, ...
> > On Jul 25, 2019, at 4:32 PM, Wietse Venema <[hidden email]> wrote:
> > default_transport = lmtp
> > relayhost = [mail.example.com]