This document explains how to enable SMTP authentication for the Mozilla Thunderbird Mail client for both Windows and Macintosh computers.


  1. Open Thunderbird Mail. From the Tools menu select Account Settings. The Account Settings box appears.

  2. In the white area on the left, select the entry Outgoing Server (SMTP). The Outgoing Server (SMTP) Settings appear on the right.

  3. In the list of servers, select the entry for smtp.gn.apc.org and click Edit

  4. Ensure that the settings are as follows:
    • Server Name: smtp.gn.apc.org
    • Port: 587
    • Connection security: STARTTLS
    • Authentication method: Normal Password
    • User Name: Your GreenNet username (the part of your email address before the “@” sign if using an @gn.apc.org address)

  5. Click the OK button, and then click OK again


Authentication has now been enabled. Please note, you will be prompted for your password the first time that you send email. You can tick the box “Use Password Manager to remember the password” to avoid having to enter it every time that you send email.