1. Sign in to Liferay Portal as admin user.
2. Configure using Control Panel > Server Administration > Mail
3. Navigate to "Control Panel > Server Administration > Mail"
4. Edit POP and SMTP mail settings.
Incoming POP Settings
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Incomding POP Server: pop.gmail.com
Incoming Port: 996
Use a Secure Network Connection: YES
User Name: EMAIL-ADDRESS
Password: EMAIL-PASSWORD
Outgoing SMTP Server Settings
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Outgoing SMTP Server: smtp.gmail.com
Outgoing Port: 465
Use a Secure Network Connection: YES
User Name: EMAIL-ADDRESS
Password: EMAIL-PASSWORD