Setting up Google Mail as Notification Server
To set Google Mail as a notification server for TeamCity, configure these options in Administration | Email Notifier page, set the options as described below:
Send email messages from
Email address to send notifications from.
Full username with domain part if you use Google Apps for domain
User's GMail password. If you get the "Username and Password not accepted" error when testing your connection, try replacing the user password with an App Password.