FreeBSD 11.2

Postfix 3.3.2

Dovecot 2.3.4

I am trying to use dovecot lmtp with postfix to verify authentication of incoming email and to avoid being a spam relay (an issue I was having using sendmail as my MTA).

I am getting the following log message in /var/log/maillog:

Mar 30 20:31:38 ns postfix/smtpd[40373]: NOQUEUE: reject: RCPT from mail-eopbgr750091.outbound.protection.outlook.com[40.107.75.91]: 450 4.1.1 <mahan@mahan.org>: Recipient address rejected: unverified address: host ns.mahan.org[private/dovecot-lmtp] said: 550 5.1.1 <mahan@mahan.org> User doesn't exist: mahan@mahan.org (in reply to RCPT TO command); from=<pmahan@silver-peak.com> to=<mahan@mahan.org> proto=ESMTP helo=<NAM02-BL2-obe.outbound.protection.outlook.com>

'mahan' does exist on ns.mahan.org. So I am confused to why lmtp is failing to find this username.

Thanks,

Patrick