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

After using the refresh firefox option that was provided to me yesterday I am now having issues with accessing sites what can I do?

  • 4 отговора
  • 2 имат този проблем
  • 11 изгледи
  • Последен отговор от jscher2000

more options

Yesterday I received the pop up that my Firefox was running slow and that I should use the refresh option. I used the refresh option and afterwards I was unable to access simple everyday web pages, and the option to add an exception is not there. Some pages I am unable to access are,, and others that I use for work. Those websites worked prior to that refresh yesterday and also the websites work on internet explorer and chrome. Please help me fix this as Firefox is my preferred browser. Here is the error and I have tried all of the steps listed on the help but still not working. I have even had my work IT department try and they advised that I speak with you because none of those recommendations are working even using an old profile. Your connection is not secure

The owner of has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website.

This site uses HTTP Strict Transport Security (HSTS) to specify that Firefox may only connect to it securely. As a result, it is not possible to add an exception for this certificate. uses an invalid security certificate. The certificate is not trusted because the issuer certificate is unknown. The server might not be sending the appropriate intermediate certificates. An additional root certificate may need to be imported. Error code: SEC_ERROR_UNKNOWN_ISSUER

All Replies (4)

more options

Hi amara20, the most common reasons users get the SEC_ERROR_UNKNOWN_ISSUER error page are listed in the following article:

How to troubleshoot security error codes on secure websites

Does anything there help you solve this problem?

more options


None of those steps have solved the problem. I'm still experiencing the same issue and not able to access certain web pages. Does anyone have anything else that may work to resolve this?

more options

Hi , There are these :

But I suggest : uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's(Win10)) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

Reinstall with Current Release Firefox 58.0.2 with a Full Version Installer

Please let us know if this solved your issue or if need further assistance.

more options

Hi amara20, does this problem only occur on a work network, or does it affect you on other networks as well?

Let's take a look at the certificate that Firefox objects to.

If you click the SEC_ERROR_UNKNOWN_ISSUER code on the error page, it should open a panel with certificate information. The encoded certificate looks like a large block of gibberish. If you see that, please click the button to copy it and then paste it into a reply. Then we can decode the certificate and get a better idea of what's going on.

If you do not get a large block of gibberish when clicking that link:

You may need to investigate using a different site that is a little less strict with its security. For example:

Do you get the error there?

Assuming so: click the Advanced button, then click the "Add Exception" button (see first screenshot below). We're not really going to add an exception, but we can get a better view of the certificate here.

In the Add Exception dialog, click the "View" button to pop up a certificate viewer. The interesting part is the "Issued by" section. I've marked that on the second screenshot for reference.

On my site, the "Issued by" section shows me "Let's Encrypt Authority X3". What do you see there?

(These example screenshots are from a test page, not my site)