• I confirm that with disabled KeeFox, Thunderbird remembers the oauth token. Restarting Thunderbird I had read/write access to the Google calendar without the login prompt. Once I re-enable KeeFox, the issue of the Oauth login window comes back and I am being asked to authorize with every restart of Thunderbird.
• Non-OAuth compatible email apps. Outlook 2010, 2013, 2016, 2019; Mozilla Thunderbird; Windows Mail on personal computers running Windows 8 or older; Apple Mail/Mac Mail on macOS 10.10/Yosemite or older; We suggest you switch to an email app that has OAuth.
• Unfortunately, this not only allows email providers to block specific email clients (which is contrary to the idea of Open-Source), but also makes it impossible to support arbitrary OAuth2 servers. That's why Thunderbird is forced to hardcode the servers that it supports and the respecive client keys.

1. Thunderbird Modern Auth
2. Oauth2 Thunderbird Yahoo
3. Oauth2 Thunderbird 2

I got this message today from my ISP/Email provider. Will I still have access to my Frontier/Yahoo email account through T-Bird? Or am I going to be forced to deal with the crappy browser based access?

Using Thunderbird with Gmail and OAuth2 allows you to overcome Google's blocking of 'less secure apps'. By using IMAP (and SMTP), you can set-up Thunderbird to handle OAuth2 authentication just fine, and not just with Google but also with other providers.

Hi,
We noticed that you are accessing your Frontier Mail using a lower security sign-in that is sometimes used in third-party mail applications such as Outlook, IncrediMail, MacMail, Mozilla Thunderbird and others. This can leave your Frontier Mail account vulnerable.

Thunderbird Modern Auth

Frontier email uses the Yahoo email platform. Yahoo is in the process of moving users using less secure apps to a newer, more secure email access technology. This security technology, known as OAuth, helps prevent unauthorized access to your username and password. With OAuth, your log in credentials are encrypted and better protected from hackers.
We will be rolling out this change beginning May 1st, 2017 through May 31, 2017. You will be impacted at any time during this time period, so we encourage you to take steps outlined here no later than May 1st, 2017.
Access your mail via frontier.yahoo.com or with a mail client that supports OAuth
Upgrade your current mail client to a version that supports OAuth
Visit https://security.frontier.com/ and create an app-specific password
For more information, a list of clients that support OAuth and step-by-step instructions, please see our help page: https://frontier.com/helpcenter/categor ... ty-upgrade
Thank you for being a Frontier Mail user.

Oauth2 Thunderbird Yahoo

Sincerely,
Frontier Technical Support

Oauth2 Thunderbird 2

1-877-937-8330