This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

I am getting 'SEC_ERROR_UNKNOWN_ISSUER' trying to open certain sites running AVG and I do not experiance the same problems in other browsers.

more options

I run AVG internet security as my anti virus. The existing Mozilla support page does not indicate a solution for AVG anti-virus. The problem originated a couple of days ago and since then i have run multiple anti virus programs trying to rule out malware including running them while booted in safe mode. I primarily get the error when using the search function of the address bar and until now I could usually open google then search directly from google.com and get around the error. As of this question i can no longer reach google to use it as a work around. I do not experience any insecure connection problem when running google chrome or internet explorer. I have removed and re-downloaded both AVG and Firefox I have made sure my Firefox proxy setting is set to auto-detect proxy settings

I run AVG internet security as my anti virus. The existing Mozilla support page does not indicate a solution for AVG anti-virus. The problem originated a couple of days ago and since then i have run multiple anti virus programs trying to rule out malware including running them while booted in safe mode. I primarily get the error when using the search function of the address bar and until now I could usually open google then search directly from google.com and get around the error. As of this question i can no longer reach google to use it as a work around. I do not experience any insecure connection problem when running google chrome or internet explorer. I have removed and re-downloaded both AVG and Firefox I have made sure my Firefox proxy setting is set to auto-detect proxy settings

All Replies (20)

more options

hello, could you give us more information about the error by clicking on the error code, copying the text to the clipboard and then pasting it here into a reply in the forum (like shown on the screenshot).

thank you!

more options

https://www.google.com/search?q=google&ie=utf-8&oe=utf-8

Peer’s Certificate issuer is not recognized.

HTTP Strict Transport Security: false HTTP Public Key Pinning: true

Certificate chain:

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Modified by cor-el

more options

thanks, the details of this certificate look very strange - mostly blank (& certainly not something like google would use):

Issuer CN = *.com
Subject CN = *.com
Valid From 26 Dec 2016, 9:36 a.m.
Valid To 25 Dec 2021, 9:36 a.m.
Serial Number 9D:10:20:AC:10:4D:6D:0F (11317581786962029839)
CA Cert Yes
Key Size 2048 bits
Fingerprint (SHA-1) CE:7A:EB:61:1C:78:4E:F1:59:F6:F9:C1:6F:C5:E1:DE:9A:7C:6F:B7
Fingerprint (MD5) 15:FE:DB:CC:2C:F4:27:C1:9E:54:84:50:1F:6A:2F:42

can you connect any particular activity like installing a program on your computer to that Valid From date?

in addition please try to refresh firefox and see if this can address the issue. one more thing to try would be to check in the firefox menu ≡ > options > advanced > network > connection - settings... that firefox is set up to directly connect to the internet ('no proxy').

more options

i have refreshed Firefox as well as changed the setting to 'no proxy'. on December 26 the computer would have been connected to the internet however i was away that day and did not use the computer. The problem has now developed in chrome as well. Is it possible this is a virus that has survived my attempts to remove it? If so how do you suggest i go about cleaning it out?

Thanks for all your help

more options

Do a malware check with several malware scanning programs on the Windows computer.

Please scan with all programs because each program detects different malware. All these programs have free versions.

Make sure you update each program to get the latest version of their databases before doing a scan.

You can also do a check for a rootkit infection with TDSSKiller.

See also:

more options

Okay, I have now run the antivirus programs suggested and removed the items they found however the problem remains unresolved.

more options

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

more options

Could you inspect the certificate for https://www.google.com/ in Chrome and see what it looks like there? Click the padlock in the address bar, then the Details link in the first section, then the View Certificate button. Please see the attached screenshot for comparison. Is it similarly suspicious?

more options

here are the certificates from chrome. the one is taken from google.com when it said my connection was secure. the other is from a website i know was secure before this problem began occuring but is now insecure.

more options

That Google Ad Services cert looks like the same interceptor you got in Firefox. It's really hard to search for web pages mentioning "*.com" certificate errors so they were very clever there.

Since this started, have you tried power cycling your router in case its memory has become corrupted? (In other words, unplug it, wait 10 seconds, then plug it back in again.)

Within Windows, you could try switching your name servers (DNS servers) to using OpenDNS instead of your ISP, in case there is a problem at your ISP. More info: https://www.opendns.com/home-internet-security/

more options

www.google.com

this is dated the same as the one from firefox

more options

I will try a power cycle next. the boot in safe mode with networking did not seem to make any difference. I have experianced the problem on multiple wifi networks.

more options

I have now rebooted the wifi with no improvement. when looking inside my servers i came across as file named 'demonware' could this possibly be a problem? I recognize most of the other names on this page but this is unfamiliar to me.

more options

When I search it, DemonwarePortMapping seems related to some gaming products. If you aren't a gamer, try turning it off. Similar for any others you don't use. You can always turn them back on if something suddenly stops working.

What do you have on the DNS tab? Usually it would be automatic, meaning, get your DNS servers from upstream at your ISP. Anything unexpected there?

more options

This is the DNS screen. i do not notice anything immediately wrong here but i amalso unfamiliar with what should be shown on this page.

more options

At this point would a full reset be my best option to clear this out?

more options

watson-97 said

At this point would a full reset be my best option to clear this out?

A full reset of what? Your router?

Not sure if this thread is helpful/relevant: How do I use custom DNS settings on the CGN3ACSMR modem? - Rogers Community

more options

A full factory reset of the computer to wipe the drives.

more options

I personally would consider that a last resort, but having run out of other ideas, perhaps you'll need to do that.

You could try the advanced malware forums listed in the support article to see whether the tools they recommend can pick up something that was missed before:

Troubleshoot Firefox issues caused by malware

more options

Also, if you didn't try changing the DNS in your router to the OpenDNS servers, I think that would be worth a try.

  1. 1
  2. 2