Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. Is the problem still there?

Start your Computer in safe mode with networking. Then start Firefox. Try Safe web sites. Is the problem still there?

Starting The Computer In Safe Mode;
Free Online Encyclopedia

Thanks for the help appologizies for the delay.

The problem doesn't happen often, but when it does it happens constantly. I got the error again and tried to open in safe mode. Opening in safemode allowed me access to the site that I couldn't get into

Not sure if it worked cause of safe mode or because it restarted firefox. Your help is appreciated! What do you recomend next?

MonkeyB said

The problem doesn't happen often, but when it does it happens constantly.

Next time, if you check the Technical Details, could you post the code(s) for the error? For example, unknown issuer, etc.

If it is unknown issuer, to gather further information, you could inspect a sample certificate to see whether that points to the culprit. For example, you could try my test page at:

https://jeffersonscher.com/res/jstest.php

Assuming you get an error page, expand the "I understand the risks" section and look for an Add Exception button.

Note: You don't need to complete the process of adding an exception -- I suggest not adding one until we know this isn't a malware issue -- but you can use the dialog to view the information that makes Firefox suspicious.

Click Add Exception, and the certificate exception dialog should open.

Click the View button. If View is not enabled, try the Get Certificate button first.

This should pop up the Certificate Viewer. Look at the "Issued by" section, and on the Details tab, the Certificate Hierarchy. What do you see there? I have attached a screen shot for comparison.

If you can't inspect the certificate via "I Understand the Risks" then try this:

Open the "Add Security Exception" window by pasting this chrome URL in the Firefox location/address bar and check the certificate:

• chrome://pippki/content/exceptionDialog.xul

In the location field of this window type or paste the URL of the website.

• retrieve the certificate via the "Get certificate" button
• click the "View..." button to inspect the certificate in the Certificate Viewer

You can inspect details like the issuer and the certificate chain in the Details tab of the Certificate Viewer. Check who is the issuer of the certificate. If necessary then you can attach a screenshot that shows the certificate viewer.

Thanks for the help. I've attached 3 images of the pages requested. Let me know if you would require further information. Thanks

@cor-el. sorry, I clicked no by accident when it asked if your info was usefull. not sure how I can change it to a yes.

Just click Yes.