/etc/ssmtp/ssmtp.conf

Default Ubuntu

cat /etc/ssmtp/ssmtp.conf | grep -v "#"  | grep .
root=postmaster
mailhub=mail
hostname=yourmachineName

Default Amazon Linux:

cat /etc/ssmtp/ssmtp.conf | grep -v "#"  | grep .
root=postmaster
mailhub=mail
TLS_CA_File=/etc/pki/tls/certs/ca-bundle.crt

Example for Gmail

[email protected]
mailhub=smtp.gmail.com:465
FromLineOverride=YES
[email protected]
AuthPass=yourpassword
UseTLS=YES

https://unix.stackexchange.com/a/363815

echo "My first email" | ssmtp [email protected]

echo "My first email" | ssmtp [email protected]
ssmtp: Authorization failed (535 5.7.8  https://support.google.com/mail/?p=BadCredentials 
y26-20020a1c4b1a000000b003ef62deb830sm6320083wma.25 - gsmtp)

Solution: check your username and password.

echo "My first email" | ssmtp [email protected]
ssmtp: Authorization failed (534 5.7.9 
https://support.google.com/mail/p=InvalidSecondFactor l32-20020a05600c1d2000b003f0321c22basm5246080wms.12 - gsmtp)

ssmtp: Authorization failed (535 5.7.8  https://support.google.com/mail/?p=BadCredentials z20- 20020a7bc7d4000000b003eeb1d6a470sm6437612wmk.13 - gsmtp)

Default Ubuntu

/etc/ssmtp/ssmtp.conf

#
# Config file for sSMTP sendmail
#
# The person who gets all mail for userids < 1000
# Make this empty to disable rewriting.
root=postmaster

# The place where the mail goes. The actual machine name is required no
# MX records are consulted. Commonly mailhosts are named mail.domain.com
mailhub=mail

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

# The full hostname
hostname=Think.localdomain

# Are users allowed to set their own From: address?
# YES - Allow the user to specify their own From: address
# NO - Use the system generated From: address
#FromLineOverride=YES

Related

• mailx

See also

• ssmtp, /etc/ssmtp/ssmtp.conf, /etc/ssmtp/
• Mail, email: Postfix, mail, SMTP, LMTP, POP3, IMAP, mailutils, amavis, Gmail, iCloud, ssmtp, msmtp