[root@poyuzd ~]# echo "test_message" | ssmtp -v "example@yandex.ru"
ssmtp: Cannot open smtp.gmail.com:587 

TLS_CA_FILE=/etc/pki/tls/certs/ca-bundle.crt
root=example@gmail.com

mailhub=smtp.gmail.com:587

# Where will the mail seem to come from?
rewriteDomain=gmail.com

# The full hostname
hostname=smtp.gmail.com:587
FromLineOverride=YES
UseTLS=YES
AuthMethod=LOGIN
AuthUser=example@gmail.com
UseSTARTTLS=YES
AuthPass=example
# Are users allowed to set their own From: address? 

root:example.com:smtp.gmail.com:587
username:example@gmail.com:smtp.gmail.com:587 

 tail -f /var/log/maillog
May  5 13:12:01 poyuzd sSMTP[25127]: Unable to locate smtp.gmail.com
May  5 13:12:01 poyuzd sSMTP[25127]: Cannot open smtp.gmail.com:587
May  5 13:12:01 poyuzd sSMTP[25126]: Unable to locate smtp.gmail.com
May  5 13:12:01 poyuzd sSMTP[25126]: Cannot open smtp.gmail.com:587
May  5 13:12:01 poyuzd sSMTP[24863]: Unable to locate smtp.gmail.com
May  5 13:12:01 poyuzd sSMTP[24863]: Cannot open smtp.gmail.com:587
May  5 13:12:01 poyuzd sSMTP[24869]: Unable to locate smtp.gmail.com
May  5 13:12:01 poyuzd sSMTP[24869]: Cannot open smtp.gmail.com:587
May  5 13:12:04 poyuzd sSMTP[25158]: Unable to locate smtp.gmail.com
May  5 13:12:04 poyuzd sSMTP[25158]: Cannot open smtp.gmail.com:587

 May  2 15:30:04 poyuzd postfix/pickup[23899]: 7D8ED832BE65: uid=0 from=<root>
May  2 15:30:04 poyuzd postfix/cleanup[24039]: 7D8ED832BE65: message-id=<2017050                                2123004.7D8ED832BE65@poyuzd>
May  2 15:30:04 poyuzd postfix/qmgr[22568]: 7D8ED832BE65: from=<root@poyuzd.loca                                ldomain>, size=1554, nrcpt=1 (queue active)
May  2 15:30:04 poyuzd postfix/error[22583]: 7D8ED832BE65: to=<root@poyuzd.local                                domain>, orig_to=<root>, relay=none, delay=0.02, delays=0.02/0/0/0, dsn=4.4.3, s                                tatus=deferred (delivery temporarily suspended: Host or domain name not found. N                                ame service error for name=smtp.gmail.com type=AAAA: Host not found, try again)

myhostname = poyuzd
relayhost = [smtp.gmail.com]:587
smtp_use_tls = yes
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_tls_CAfile = /etc/ssl/certs/ca-bundle.crt
smtp_sasl_security_options = noanonymous
smtp_sasl_tls_security_options = noanonymous 

# systemctl start httpd
Job for httpd.service failed because the control process exited with error code. See "systemctl status httpd.service" and "journalctl -xe" for details.
# systemctl status httpd.service
● httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Fri 2017-03-24 14:14:00 MSK; 1min 41s ago
     Docs: man:httpd(8)
           man:apachectl(8)
  Process: 18060 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=1/FAILURE)
  Process: 18058 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=exited, status=1/FAILURE)
 Main PID: 18058 (code=exited, status=1/FAILURE)

Mar 24 14:14:00 poyuzd httpd[18058]: (98)Address already in use: AH00072: make_sock: could not b...]:80
Mar 24 14:14:00 poyuzd httpd[18058]: (98)Address already in use: AH00072: make_sock: could not b...0:80
Mar 24 14:14:00 poyuzd httpd[18058]: no listening sockets available, shutting down
Mar 24 14:14:00 poyuzd httpd[18058]: AH00015: Unable to open logs
Mar 24 14:14:00 poyuzd systemd[1]: httpd.service: main process exited, code=exited, status=1/FAILURE
Mar 24 14:14:00 poyuzd kill[18060]: kill: cannot find process ""
Mar 24 14:14:00 poyuzd systemd[1]: httpd.service: control process exited, code=exited status=1
Mar 24 14:14:00 poyuzd systemd[1]: Failed to start The Apache HTTP Server.
Mar 24 14:14:00 poyuzd systemd[1]: Unit httpd.service entered failed state.
Mar 24 14:14:00 poyuzd systemd[1]: httpd.service failed.
Hint: Some lines were ellipsized, use -l to show in full.