Zimbra Enforcing a match between FROM address and sasl username

zmprov mcf zimbraMtaSmtpdRejectUnlistedRecipient yes zmprov mcf zimbraMtaSmtpdRejectUnlistedSender yes zmprov mcf zimbraMtaSmtpdSenderLoginMaps  proxy:ldap:/opt/zimbra/conf/ldap-slm.cf +zimbraMtaSmtpdSenderRestrictions reject_authenticated_sender_login_mismatch vi /opt/zimbra/conf/zmconfigd/smtpd_sender_restrictions.cf

Add reject_sender_login_mismatch to the the line

permit_mynetworks, reject_sender_login_mismatch zmmtactl restart zmconfigdctl restart

Test your SMTP Configuration from this site https://www.wormly.com/test-smtp-server