READ: https://devanswers.co/configure-postfix-to-use-gmail-smtp-on-ubuntu-16-04-digitalocean-droplet/ Prerequisites If your Gmail account uses 2-Step Verification, you must create an application specific password. If you’re not using 2-Step Verification, please ensure that your Gmail account is configured to allow less secures apps. Remove sendmail [crayon-6a2d1689bbd82756894554/] 1. Install Postfix [crayon-6a2d1689bbd89171630361/] Let’s update the package database first. On the first Postfix configuration screen, select OK by pressing TAB … Continue reading Setup Postfix on Ubuntu 16.04 Localhost and Use Gmail SMTP