Hi, If the primary send a 550, the reply is no.
Regards > De: "Wyatt Chun" <wyattc...@gmail.com> > À: "Postfix users" <postfix-users@postfix.org> > Envoyé: Mardi 17 Mars 2020 07:37:30 > Objet: about secondary MX > Hello > If the primary MX server returns "mailbox full" error, will the delivery agent > try to send message to the secondary MX? > [ http://example.de/ | example.de ] . 299 IN MX 10 [ http://secondary.mx/ | > secondary.mx ] . > [ http://example.de/ | example.de ] . 299 IN MX 5 [ http://primary.mx/ | > primary.mx ] . > Thank you.