After the latest Avast update I get an error message in Outlook: “The server you are connected to is using a security certificate that cannot be verified. A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider.”
The certificate is issued by Avast Web/Mail Shield Untrusted Root
How should I solve this problem?
I’m getting something similar with Thunderbird. It looks as if new certificates have been added somewhere which are judged invalid.
In Thunderbird there is an override but it is not working consistently with Gmail (pop).
It is unfortunate that this problem has appeared. I wonder if it is the same bug that was reported during beta testing.
Be that as it may, is there a work round please?
Free Version 21.5.2470 running on Window 10 20H2
I believe this is the bug I reported during beta testing 
If your mail client have “exceptions” feature, go ahead with it, otherwise you have to turn mail shield off temporarily.
New to the Forum. Came here because I’m getting the same msg in Thunderbird and Windows Live Mail. I was able to override in Thunderbird. In Windows Live Mail, I just hit the button to proceed Yes
Just want to make sure that it’s a bug w/the new upgrade and based on the comments, it appears that it is. How do we report to Avast?
Thanks!
P.S. Also added other mail clients to the subject in case others are searching; Hope that’s ok.
Hi guys, we were integrating certificate processing code between MailShield and WebShield and this must have somehow slipped through the checks. We have seen this in the BETA and fixed it - well, at least that’s what we thought!
The team is working on it while I type … we’ll update you here soon.
Lukas
Guys, we already have a fix for you. Testing it now if it covers all the cases!
I have been getting this notice with each mail account (3 accounts) I use with Thunderbird for the last several weeks.
I have to ‘confirm exception’ for each account every time I open (execute) Thunderbird. The exception is never saved.
Once I confirm exception then I can retrieve mail.
Nothing happens when ‘Get Certificate’ is chosen.
I have the same issue with Thunderbird. Confirm exception does not work. If I turn off mail shield I can get mail, BUT, then my ‘pre-mail’ program, Mailwasher will not receive mail. Mailwasher works with mail shield on.
I have the same problem since an update I think yesterday 6-16-2021, all was fine before that with mail shield on.
All mail into and out of Thunderbird is blocked with mail shield on.
I found a post about adding a certificate but it was above my head. Can I hope this is being addressed?
Can Avast be rolled back?
I’m on 21.5.2470 (build 21.5.6354.561)
hi,
future update or emergency update already released?
As far as I’m concerned the problem is still present (Thunderbird , W7 64)
Sounds like it’s still being tested and hasn’t been released yet. Is that correct?
Hi,
It will be released soon.
My version updated to build 21.5.6354.675 this morning and the Mail Shield issue is now resolved in my case.
confirmed for me too … after reboot
OK here now too but a reboot is essential.
A word of thanks to the Avast team for sorting this.
How to update to build 21.5.6354.675
Same issues here in the states. Disabled mail scanner to get traffic and awaiting update or procedure to re-enable it.
OK with build .675 I can confirm the issue is resolved now. 8)
On icarus channel this build (uupdate) does not come and still with .439, waiting for .675
All working as it should here now.
Thanks, Nice job! 
I still have Version: 21.5.2470 (build 21.5.6354.561) It did not update and I still have the same problem. What is the process for rebooting? Just restarting my computer?