My server is running on Ubuntu 14.04 and I have Postfix installed. When I send something to my gmail account, it goes to spam. I set up SPF, DKIM and DMARC, here is a confirmation:

Authentication-Results: mx.google.com;
   dkim=pass header.i=@mydomain.com;
   spf=pass (google.com: domain of office@mydomain.com designates xxx.xxx.xx.xxx as permitted sender) smtp.mailfrom=office@mydomain.com;
   dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=mydomain.com

But there's a red padlock saying: encryption: mydomain.com did not encrypt this message.

Emails from others have such a note: encryption: Standard (TLS)

Could you help me a little with this, what should I do? Might it be a reason that emails from my server go to spam? Thanks in advance.

My /etc/postfix/main.cf:

biff = no
append_dot_mydomain = no
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_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = mail.mydomain.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = mydomain.com, bociuch, localhost.localdomain, localhost
relayhost = 
mynetworks = [::ffff:]/104 [::1]/128
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all

milter_protocol = 2
milter_default_action = accept
smtpd_milters = inet:localhost:12301
non_smtpd_milters = inet:localhost:12301
  • Your postfix config would be helpful. Jun 1 '17 at 8:21
  • My initial post updated.
    – BociucH
    Jun 1 '17 at 8:28

You are missing the smtp_tls_security_level directive.

smtp_tls_security_level = may

This will set it to opportunistic TLS, using encrypted connections if the server supports it, but allowing unencrypted connections if the server doesn't.

The default value for smtp_tls_security_level is none.

  • After adding it, everything works fine. Many thanks!
    – BociucH
    Jun 1 '17 at 8:34
  • 1
    after 14 hours of knocking my head with gmail....its a shame i cant vote up u only one time... or not? Oct 18 '19 at 1:59
  • Surely you can figure out some way MacGyver ;) Oct 13 '20 at 23:09
  • Wow, what simple..., I wonder why the default isn't "may" for this option. Jan 6 at 2:49

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