Email Tutorials - Herong's Tutorial Examples - v1.04, by Herong Yang
Thunderbird to Accept POP3S Certificate Exception
This section provides a tutorial example on how to handle POP3S server Certificate Exception on Thunderbird. Just click 'Confirm Security Exception' to accept and store the default certificate provided by Dovecot server.
If you are running a POP3S (POP3 over SSL/TLS) service with Dovecot, a dummy self-signed root certificate by default.
When you connect Thunderbird to this POP3S service for the first time, you will get certificate exception. Don't worry. Here is how you can handle this exception.
1. Click "Confirm Security Exception". This tells Thunderbird to accept and store this certificate.
2. Click "Get Messages" to continue retrieving emails from the POP3S server.
If you are curious about this dummy self-signed root certificate, click "Thunderbird > Preferences > Privacy & Security" menu. Then click "Manage Certificates" to open it. The dummy certificate shows the following:
Subject Name
Organizational Unit: IMAP server
Common Name: imap.example.com
Email Address: postmaster@example.com
...
The subject name, IMAP server, suggests that Dovecot is sharing the same dummy certificate for both IMAPS and POP3S service.
If you don't like this default certificate, read Dovecot tutorials to replace it with your own certificate.
You also need to accept the security exception when composing and sending new email messages using the SMTP with STARTTLS service.
Table of Contents
Postfix - Mail Transport Agent (MTA)
SSL/TLS Secure Connections with Postfix Server
Dovecot - IMAP and POP3 Server
SSL/TLS Secure Connections with Dovecot Server
Email Client Tools - Mail User Agents (MUA)
►Mozilla Thunderbird - Mail User Agents (MUA)
Thunderbird Installation on macOS and Windows
Thunderbird Configuration for POP3S and SMTP
►Thunderbird to Accept POP3S Certificate Exception
Thunderbird Configuration for IMAPS and SMTP
Thunderbird Configuration for SMTPS Service
Manage Security Certificates on Thunderbird
Send Message Errors on Thunderbird
PHPMailer - PHP Package for Sending Emails