Users can emails either using Partenero's e-mail server or a 3rd party e-mail service via SMTP.
Steps to send e-mails via SMTP:
Go to Partenero > Settings > Email Configuration
Set "Send emails using" as "SMTP"
Set "Host" as the SMTP server from your e-mail provider
Set "Port" as the SMTP port from your e-mail provider
Set "User" as your e-mail
Set "Password" as your e-mail password
Send a test email by filling up the field in front of the button "Send test email to" and then pressing the button