Postfix + Microsoft Outlook [Connects to incoming server, but not outgoing]

I followed this tutorial to install Postfix to prepare myself to be able to once again use Microsoft Outlook to check emails.

I think most of it is set up correctly. Through adding a new account in Outlook, I am able to successfully connect to the incoming mail server. However, I am unable to connect to the outgoing (SMTP) mail server. Both servers are listed as “”, with ports 993 for incoming and 25 for outgoing (both using SSL). I also have SSL setup through LetsEncrypt, which is where the certs point to in the file below (this file is a bit of a mess from trying to pull from different sources to make this work).

# See /usr/share/postfix/ for a commented, more complete version

# Debian specific:  Specifying a file name will cause the first
# line of that file to be used as the name.  The Debian default
# is /etc/mailname.
myorigin =

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# TLS parameters
#smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
#smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_tls_auth_only = yes

smtpd_tls_loglevel = 1

# Disable SSLv2/3 as they are vulnerable
smtpd_tls_protocols = !SSLv2, !SSLv3
smtp_tls_protocols = !SSLv2, !SSLv3
# Insist on stronger ciphers
smtpd_tls_ciphers = high
smtp_tls_ciphers = high
broken_sasl_auth_clients = yes
smtp_tls_cert_file = /etc/letsencrypt/live/
smtp_tls_key_file = /etc/letsencrypt/live/

smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_auth_enable = yes
smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,reject_unauth_destination

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = Mmaengineer
alias_maps = hash:/etc/aliases proxy:pgsql:/etc/postfix/
local_recipient_maps = proxy:pgsql:/etc/postfix/ $alias_maps
alias_database = hash:/etc/aliases
mydestination = Mmaengineer, localhost.localdomain, , localhost
relayhost =
mynetworks = [::ffff:]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all

mailbox_transport = lmtp:unix:private/dovecot-lmtp
virtual_transport = lmtp:unix:private/dovecot-lmtp
virtual_mailbox_domains = mysql:/etc/postfix/
virtual_mailbox_maps = mysql:/etc/postfix/
virtual_alias_maps = mysql:/etc/postfix/

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Accepted Answer

@tylerdd91d55f77 - Now that your config settings work, you need to set up your SPF, DKIM, and DMARC records for gmail to not mark your mail as spam. Look in the bottom of this page with the “Related Questions” section to get details of how to create those DNS records, or use the search bar on the upper part of this page. Good luck.

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