сайты-доступные подпапки и a2ensite?

Запуск:

sudo apt-get install ssmtp
sudo -H gedit /etc/ssmtp/ssmtp.conf

Здесь должно быть добавлено следующее:

# The user that gets all the mails (UID < 1000, usually the admin)
root=yourusernameofgmail@gmail.com

# The mail server (where the mail is sent to), both port 465 or 587 should be acceptable
# See also https://support.google.com/mail/answer/78799
mailhub=smtp.gmail.com:587

# The address where the mail appears to come from for user authentication.
rewriteDomain=gmail.com

# Use SSL/TLS before starting negotiation
UseTLS=Yes
UseSTARTTLS=Yes

# Username/Password
AuthUser=yourusernameofgmail
AuthPass=yourGmailPassowrd
AuthMethod=LOGIN

# Email 'From header's can override the default domain?
FromLineOverride=yes

Запустить :

sudo -H gedit /etc/ssmtp/revaliases

Войдите туда:

root:yourusernameofgmail@gmail.com:smtp.gmail.com:587

Включите «менее безопасные приложения» в Gmail: https://support.google.com/accounts/answer/6010255?hl=ru&!d6]

Включить «менее безопасные приложения» в Gmail:

echo "Body of mail is abc" | mail -s "Subject is xyz" "someusername@gmail.com"`