Fix Thunderbird Add Security Exception

I see a security exception warning in Thunderbird. How can I fix it?

Problem

When you access your email in Thunderbird the following error can occur:

Add Security Exception
You are about to override how Thunderbird identifies this site.

Symptom

  • When you open or send and receive email from Thunderbird the error is shown.

Cause

Thunderbird cannot verify the SSL certificate of the incoming or outgoing server and create a secure connection. This may be caused by Thunderbird using incorrect email settings.

Resolution

Check your incoming and outgoing server names are set correctly in Thunderbird.