1. Turn on 2-factor authentication in Google and generate the app password which will be used by the pi.
2. Install packages:
sudo apt-get install msmtp msmtp-mta mailutils
3. Put the following in /etc/msmtprc
# Generics defaults auth on tls on # following is different from ssmtp: tls_trust_file /etc/ssl/certs/ca-certificates.crt # user specific log location, otherwise use /var/log/msmtp.log, however, # this will create an access violation if you are user pi, and have not changes the access rights logfile ~/.msmtp.log # Gmail specifics account gmail host smtp.gmail.com port 587 from root@raspi-buster user your-gmail-accountname@gmail.com password your-gmail-account-password # Default account default : gmail
4. Test
echo 'message' | mail -s "raspi-buster" destination-email-address@gmail.com