Mail can't verify the identity of the server "mail.talktalk.net"

AVG Protection
1

My laptop is a MAC Air book running OS X El Capitan Version 10.11.16

Mail presents this message box when trying  to connect to talktalk.net. This has only started since AVG released an update to their internet security.

 

The certificate for this server is invalid. You might be connecting to a server that is pretending to be "mail.talktalk.net" which could put your confidential information at risk. Would you like to connect to the server anyway?

 

The certificate mail.talktalk.net

issued by: AVG untrusted CA

Expires: Friday 14 May 2021 at 00:59:59 British Summer Time

X This certificate was signed by an unknown authority.

 

I tried to log on to the mail server through the talktalk web site and got a similar message in the firefox browser.
Had the same thing earlier this year with the Nat West web site. no fix found.

Why should these certificates suddenly become invalid  after an update.
Any help appreciated.

8

Hi Avinash,
The mail app is the standard one that come with the mac OS version 9.3

3

My apologies, Andy.
Please instructions in the article provided was for Windows devices.

If a mail server uses an SSL certificate that’s signed by an unknown authority (such as a self-signed certificate), the Mail app  on your Mac displays a message indicating that it can’t verify the identity of the mail server. Although you can connect to the mail server, Mail will continue to warn you about it each time you open Mail. To stop the message from appearing, indicate that you trust the mail server’s certificate.

If the Mail app on your Mac can’t verify a server or a signature, you can review the certificate that it displays.

  1. In the Verify Certificate dialogue, click Show Certificate.

  2. Review the certificate, then if you have confidence in the server or signature, select the tickbox to always trust the certificate or to acknowledge the signature is valid.

    <p>For information about current trust policies, click the Details disclosure triangle. To learn more about trust policies, see <a href="https://support.apple.com/en-gb/guide/mac-help/mchlp2824" target="_blank">Certificate trust policies</a>.</p>
</li><li>
<p>Click Connect or OK, then enter your account password (if required).</p>

<p>If the certificate is a root certificate, enter the name and password of an administrator of the Mac you’re using.</p>
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2

Hi Andy.
You might want to export the email server certificate from AVG and import it to your email client.
Could you confirm which email client are you using?

4

That's wonderful, Andy.
We're glad to hear that. Please do not hesitate to contact us if you need any assistance in future.

7

Thank you for the confirmation, Andy
I request you to follow the steps in the below article to export the email server certificate from AVG and import it to your email client
https://support.avg.com/SupportArticleView?l=en&urlName=AVG-Troubleshoot-invalid-email-certificate&q=email+certificates&supportType=home
Keep us posted.

6

Hi Avinash,
The mail app is the standard one that come with the mac OS version 9.3

5

Hi Avinash,
AVG did a virus definition at 10:28 to day, which seems to have fixed the problem.

Many thanks for your help.

Andy