Job for postfix.service failed because the control process exited with error code. See "systemctl status postfix.service" and "journalctl -xe" for details.
vi /etc/postfix/main.cf 修改以下两样为这个配置： inet_protocols = ipv4 inet_interfaces = all
原文：https://www.cnblogs.com/arebirth/p/linuxstartpostfixerror.html