# cat /etc/redhat-release
CentOS Linux release 7.3.1611 (Core)
# more /var/log/maillog
Sep 1 17:07:50 izuf6cj2o216xp postfix/sendmail[25307]: fatal: parameter inet_interfaces: no local interface found for ::1
Решил:
vim /etc/postfix/main.cf
#inet_interfaces = localhost
inet_interfaces = all
, затем
service postfix start