Certificate information error

Avast Free Antivirus / Premium Security
1

When I open Outlook in Win 10, I get this popup box “Internet Security Warning”
“The server you are connected to is using a security certificate that cannot be verified”
The target principal name is incorrect
view certificate
Do you want to continue using this server
I click ‘YES’
If I click 'view certificate , I get the following:-
" Certificate Information"
It says:- All the intended purposes of this certificate could not be verified
Issued to :- autoconfig.cp163173.hpdns.net
Issued by :- avast Web/Mail Shield Root
Valid from :- 15/06/2025 to 13/09/2025

And I click OK. My emails load even if I don’t click ‘ok’.

2

I followed Avast advice. Saved the Mailshield.der file. Uninstalled Avast free, Restarted windows. Reinstalled avast free. installed the Mailshield.der and still get the error.

3

Hi @kraken.sankey , sorry to hear about your trouble! By “followed Avast advice,” do you mean following this troubleshooting guide? https://support.avast.com/en-ww/article/troubleshoot-invalid-antivirus-email-certificate/#idt_030

If so, please note that for Outlook, you do not need to manually import the certificate - it should be enough to reinstall Avast.

As for the next steps, can you please check if the problem persist after you simply reboot your system? (no need to reinstall Avast or the DER file)

4

No. I did all that and I still have the problem. It happens every time I open outlook. That’s basically first thing in the morning and it’s open all day. A reboot is the same. Open outlook and I get the warning.

5

Thank you @kraken.sankey , can you please send us debug logs from your device? Please follow the steps below:

  1. Enable debug logging in - Avast - Menu - Settings - General - Troubleshooting.
  2. Restart your computer.
  3. Open Outlook and let it show the error. Click YES.
  4. Generate and send us logs using our “Support Tool” - the steps are described here: How to submit a support file using the Avast Support Tool | Avast
    Please enter “890034” as your ticket number.
  5. Once the logs are created, send me the “File ID” value shown on the finish screen in Support Tool.

This should allow us to investigate this particular situation.

2 Likes
6

File ID is VT52T

I hope that helps and that I did it correctly.
Martin

7

Thank you for the log file, Martin. I can confirm it was delivered correctly. I forgot to mention that you should disable debug logging in Avast Troubleshooting settings after sending the logs, to prevent unnecessary logs from being generated. I recommend that you go ahead and disable it if you haven’t already.

As for the problem itself, I see there’s a 3rd-party antivirus installed on the system - Trusteer Endpoint Protection. I’m not 100% sure if it is the culprit, but it would be useful to verify.

Do you have a possibility to uninstall Trusteer (at least temporarily)? If so, can you please uninstall it, restart your computer and then check if the problem persists?

8

I’ve gone back and turned off logging. I guess there may be 1 extra log file from powering up this morning. Do I need to delete that? If so, where will I fing it ? I uninstalled Trusteer… How did that sneak onto my PC? I didn’t knowingly install it.!!! Yes, the problem is still there. Bummer.

9

Thank you for your quick response! There should be no need to delete log files.
As for how Trusteer might have got onto your system, I’m not sure but it is often used by companies and it can be installed by system admins on workstations.
Regarding the problem itself, we are checking what might be the culprit. I will try to keep you posted.

10

Thanks. I suspect there was a small tick box somewhere, hard to see, when I installed something else and that installed Trusteer… If it helps I have outlook 2007.

11

@kraken.sankey There’s one more thing we should’ve checked at the beginning: Is this problem caused by Avast at all? If you temporarily disable Avast shields, will you still see this warning?

  • More specifically, it should be enough to disable Mail Shield temporarily in - Avast - Protection - Core Shields - by clicking the green switch and selecting “Disable for 1 hour”.
  • Once that’s done, restart Outlook and check if you’re still getting the warning (and if it still mentions Avast as certificate issuer).

We suspect that the original certificate is the culprit and that Avast only plays a passive role in this warning.

12

OK I’ll do that and report back. Thx.
That didn’t stop the message coming up. It still says Avast… What on earth is causing it then ?

13

I did notice, that going back into core shields, they were alredy turned back on. I would have thought they should have stayed off for 1 hour . PS I did reboot the PC. OK I did it again - turned off mail shield and just restarted Outlook. . Same result so it’s not Avast issue I guess…

14

Yes, this would suggest this is likely a problem with the certificate on your device or with the mail server. Potentially it may not be playing well with Outlook 2007.
If you know which particular email account is causing this issue, you can maybe try setting it up temporarily in a newer Outlook app that should be preinstalled on your device by Microsoft. If the problem does not appear in this new Outlook, it is probably the old client itself that is causing the issue.

1 Like
15

Thanks for all the advice. I’m going to install Office 2021 and see if that fixes it. Clearly NOT an Avast issue.