open /etc/postfix/main.cf and remove following lines
smtpd_milters = inet:127.0.0.1:8891
non_smtpd_milters = $smtpd_milters
milter_default_action = accept
and then restart postfix using
systemctl restart postfix
open /etc/postfix/main.cf and remove following lines
smtpd_milters = inet:127.0.0.1:8891
non_smtpd_milters = $smtpd_milters
milter_default_action = accept
and then restart postfix using
systemctl restart postfix