Unable to authenticate to Google Gmail mail servers: Secure connection failed

[Todd Taft]

I get an error "Secure connection failed" whenever I attempt to authenticate to accounts that are hosted by Google. This affects gmail.com addresses and addresses in other domains that use Google Workspaces. I am able to connect to other mail servers (e.g. ones running dovecot).

In order to make sure the problem wasn't caused by any plugin, etc. that I had installed, I reinstalled the packages and moved aside the ~/.thundirbird directory.

The problem still occurs doing the account setup phase for the Google accounts. I enter the name, address, password in the main Thunderbird window, and then get a pop-up window that asks for account name and password again. After entering that, it proceeds to ask me if I want to allow Thunderbird permission to access mail, calendars, etc., and it then asks me to do the two-factor authentication. It's after I do the two-factor authentication and click the button to indicate that I have done so that I get the error.

There should not be any outbound firewall rules blocking connections to Google servers. IPv6 does not work properly from this network, but I don't have any known problems with IPv4 connections to Google.

Ubuntu 20.04
thunderbird 1:102.8.0+build2-0ubuntu0.20.04.1
thunderbird-gnome-support :102.8.0+build2-0ubuntu0.20.04.1

[Todd Taft (taft)]

With thunderbird 1:115.3.1+build1-0ubuntu0.20.04.1 the error message has changed to a security error about accessing files on localhost. See attached image.