Avast and Mozilla Thunderbird certificate problem

[okocadere]

Thanks, Chris. Your suggestion solved the problem. You are the one solves the problem, and Asyn you are bighead useless guy just saying "NOT SUPPORTED". Chris helped me and the problem solved.

[Asyn]

Well, it is as I said, Avast officially doesn't support insider prewievs. If it works for you, good - else, bad luck.

[berge2007]

Hi, folks

I would add some extra content for this thread maybe it will useful for somebody later becuse I had to solve similar/same issue.

So after the user installed the latest version of Thunderbird  (at this time 78.4.xxx) all sending and receiving activity just stopped and TB throwed message windows with "can't validate the certificate" blabla.

First I tried to jiggling with security.tls.version.min , security.tls.version.enable-deprecated TB settings but it did not help.

After that I found a post about  the Avast / Mail shield certificate magic (https://support.avast.com/en-ww/article/91/ , https://support.avast.com/en-ww/article/Troubleshoot-invalid-email-certificate). So I saved that certificate and tried to add to TB but it replied that this certificate has already added.

I deleted the related certificates and tried to add the Mail shield certificate again, it didn't solve the problem. (Of course I've restarted TB several times between of these events)

After that I just added this certificate to Win10 "Local computer" certificate storage, and that was the solution.

TB started working but the very first time it asked confirmation of the certificate(s).

I don't know is this a really hacky or stupidly dangerous way to solve this problem, but at least I didn't have to reinstall TB, AVAST or the whole machine.