Thunderbird <-> Avast <-> Gmail broken

[FrostBitten]

Last night at 0114 was when I could last get my gmail via Thunderbird.  Nothing changed software version wise (except maybe Avast's def files) until I started troubleshooting the problem.  It keeps reporting that "connection to server pop.gmail.com was reset."  Outgoing mail is blocked saying authentication Oauth not supported service.

Upgrading to Avast (Free) 20.7 does not fix it. 

Disabling Avast's MailShield DOES fix problem.

Have Thunderbird 78.2.1, but Manifested under version 68.x.x.

It used to be that I had to force-generate a certificate through Avast that I could import into Thunderbird, but that option doesn't exist in Avast anymore.  There are three Avast Web/Mail Shield Root already in Thunderbird, valid from 2010 until 2040.

Have Windows 10 Pro, 1909.

Anyone have suggestions on what to do with this mess?

[Asyn]

See if this helps: https://support.avast.com/en-ww/article/Troubleshoot-invalid-email-certificate/

[FrostBitten]

...and with no further input from me, it started working today. SMH.

I guess they fixed it in last night's def files?

[AZBruno]

I have had intermittent problems with Thunderbird and Avast Mail Shield. In my case, the symptom are generally connection timeouts on POP3.

This has been going on for about the last three versions of Avast and the same for Thunderbird, so I don't know whose change introduced the trouble.

Don't assume it's fixed. It is intermittent.

[schmidthouse]

I'm wondering if it involves more then just Avast and Email Client. Possibly OS and system configuration.
I only wonder because I've used Thunderbird for years and Avast much longer and have never experiences any certification issues or any other kind of disruption in the functioning of Thunderbird.

[DavidR]

I'm wondering if it involves more then just Avast and Email Client. Possibly OS and system configuration.
I only wonder because I've used Thunderbird for years and Avast much longer and have never experiences any certification issues or any other kind of disruption in the functioning of Thunderbird.

Snap no problem either, been using thunderbird for may years and avast for over 16 years (much has changed in that time).  However, I don't connect to my Gmail account using thunderbird.  I do that directly from my browser.

[FrostBitten]

...and it's back again.

What the heck?  Intermittent is certainly right.

Also, trying to Import Avast's exported certificate in Thunderbird results in an error. "The certificate is already installed as a certificate authority."