I had a Windows 10 PC with thunderbird importing emails from Gmail with Avast free as my anti-virus program. No problems.
I created a new Windows 11 PC, saw the new Avast One app and decided to try it. Nothing but problems so far with thunderbird with importing gmail messages. Every time I click "Get messages" on thunderbird the following error appears in the bottom right hand corner from Windows 11's notification center: "Non-overridable TLS error occurred. Handshake error or probably the TLS version or certificate used by server imap.gmail.com is incompatible". If I disable all the avast shields for 10 minutes and I click the "Get messages" button in Thunderbird, emails get imported into Thunderbird correctly. It's Avast One causing the problems.
I tried doing a search and so far the following solutions have not worked:
1) I can't export a mail certificate following the article below. Those steps don't work for Avast One. There's no search area to find that "geek:area" menu option within the software.
https://support.avast.com/en-ww/article/91/#pc2) I saw in another forum post about remove the checkmark next to "Scan outbound emails". I tried that and it didn't work. I still get the error in the screenshot below.
My thunderbird is configured the same exact way it was on Windows 10 (I basically imported the exact Thunderbird profile to Windows 11). So that includes the following settings. "Connection security: SSL/TLS" and "Authentication method: OAuth2"
I'm using Thunderbird version 102.3.2. I'm using Avast One version Ver 22.9.6034 build 22.9.7554.750
Any help would be greatly appreciated. Thunderbird is one of the most popular email management softwares in the world.