hi, mozilla has obviously properly set-up it's website. you'll get this error when something on your system or network is tampering with secure connections. a solution depends on the individual circumstances:

• what is the error code shown when you click on advanced on that error page?
• please also 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 in the screenshot.

thank you!

>> hi, mozilla has obviously properly set-up it's website. So also, obviously, Google and Microsoft have configured their domains properly, but Firefox gives the security error for their websites as well, while IE and Chrome do not. So, keeping an open mind, I tried mozilla from home, and no problem! My apologies. It must be my corporate network, which has been known to secretly impose proxies between workstations and internet. I would provide the error number, but all I get is a blank screen in FF. After adding mozilla.com to the ignore list, I got a Mozilla page, but then the error I sent, which was apparently trying to ask for a firefox.com login. So my employer must not like Firefox.

Chrome and IE browsers DONOT get an error browsing to your URL on the exact same machine. So, I wonder what you guys did to peeve off my employer? JK LOL. I will continue to use Firefox at home. But you are dead in the water at the office, unless you do some PR and can somehow convince them to allow the same priveleges as the other 2 browsers.

You can check if there is more detail available about the issuer of the certificate.

• click the "Advanced" button show more detail
• click the blue SEC_ERROR_UNKNOWN_ISSUER message to show the certificate chain
• click "Copy text to clipboard" and paste the base64 certificate chain text in a reply

If clicking the SEC_ERROR_UNKNOWN_ISSUER text doesn't provide the certificate chain then try these steps to inspect the certificate.

• open the Server tab in the Certificate Manager
  • Options/Preferences -> Privacy & Security -> Certificates: View Certificates -> Servers: "Add Exception"
• paste the URL of the website (https://xxx.xxx) in it's Location field.

Let Firefox retrieve the certificate -> "Get Certificate"

• click the "View" button and inspect the certificate

You can see detail like the issuer of the certificate and intermediate certificates in the Details tab.

You can check the certificate chain in a browser that works and export the root certificate to a file on the desktop. Then you can import this file in the Firefox Certificate Manager. When prompted you need to set the trust bit to use the certificate to "Trust this CA to identify websites".

Note that trust bits are only required for trusted root certificates and should never be set on an intermediate certificate.

Thanks for the help. But, my job is not to figure out how to make Firefox work on our website and/or network, nor to import certificates in FF for every site I might want to visit in Firefox at work. I will continue to use FF at home, as I think it is a good browser. But my job is to help maintain a corporate website, which seems to be working fairly well in Edge, IE, and Chrome. I only posted out of frustration, when I saw so many other FF users with the same complaint after a specific upgrade version, and thought it might be helpful for Mozilla.

In the past, we have told our website customers that we only supported IE. Now we will be able to tell them IE, Chrome, and maybe Edge. If Firefox, ends up working with our new website, from outside our company network, once it goes live, we will likely advertise support for Firefox as well, with possible caveats for internal network use. Maybe we will eventually figure if our IT department is causing FF to behave oddly, or if your countless other complaints are all related to some negative change in FF. The more browsers we can list, the better, but we don't want excessive help desk calls for browsers that won't work well with our site. So we will ultimately figure out which ones work well and only list those as recommended.

Again, Thank You for trying to help, but I am done. Good luck figuring out what changed in FF that started causing issues for corporate firewalls/proxy/whatever environments that you think might be the cause.

BradGreer said

Thanks for the help. But, my job is not to figure out how to make Firefox work on our website and/or network, nor to import certificates in FF for every site I might want to visit in Firefox at work. I will continue to use FF at home, as I think it is a good browser. But my job is to help maintain a corporate website, which seems to be working fairly well in Edge, IE, and Chrome. I only posted out of frustration, when I saw so many other FF users with the same complaint after a specific upgrade version, and thought it might be helpful for Mozilla. In the past, we have told our website customers that we only supported IE. Now we will be able to tell them IE, Chrome, and maybe Edge. If Firefox, ends up working with our new website, from outside our company network, once it goes live, we will likely advertise support for Firefox as well, with possible caveats for internal network use. Maybe we will eventually figure if our IT department is causing FF to behave oddly, or if your countless other complaints are all related to some negative change in FF. The more browsers we can list, the better, but we don't want excessive help desk calls for browsers that won't work well with our site. So we will ultimately figure out which ones work well and only list those as recommended. Again, Thank You for trying to help, but I am done. Good luck figuring out what changed in FF that started causing issues for corporate firewalls/proxy/whatever environments that you think might be the cause.

Very nice. Does no good here in Firefox Volunteer Support though. Try using the 3 Bar Menu then Help --> Submit Feedback

https://blog.mozilla.org/futurereleases/2018/03/13/it-pros-and-cios-sign-up-to-try-firefox-quantum-for-enterprise/

BradGreer said

Thanks for the help. But, my job is not to figure out how to make Firefox work on our website and/or network, nor to import certificates in FF for every site I might want to visit in Firefox at work.

right, ideally that would be the job of your it department at work. however one simple trick you could try nevertheless, is to enter about:config into the firefox address bar (confirm the info message in case it shows up) & search for the preference named security.enterprise_roots.enabled. double-click it and change its value to true...

That worked! I'm glad I gave Firefox one more shot. You should consider leading with that security.enterprise_roots.enabled answer, next time. It's way less painful than [adding all sites I want to visit to the exception list].