hi, can you tell us if you are using a particular security software on your device?

There is security software like Avast and Kaspersky that intercepts secure connections and sends their own certificate or that incorporates special web shielding features that can block content.

If you can't inspect the certificate via Advanced (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 with the https:// protocol prefix (https://xxx.xxx).

• 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 please attach a screenshot that shows the Certificate Viewer.

No, no security software

Hi Mike, in your newer question you added:

Cannot load firefox as I always get the message that every site in not secure. I do not have avast or any other blocking software.
Firefox has worked fine for many years then this started yesterday. I have tried all the fixes proposed by support but nothing helps. I have a Mac 10.11 and the latest firefox

Can you think of any changes in your system or your Firefox? For example, did you use the Refresh feature? This would place an Old Firefox Data folder on your desktop. If you find that, please don't delete it yet in case we need to restore any old files from it.

When you get secure connection errors for pretty much all secure sites, the problem usually is one of the following:

(1) Error in your system's date, time, or time zone, which throws off certificate validity checks. Sometimes allowing computers to use an internet-based time source can introduce this problem.

(2) Firefox not being set up to work with your security software that intercepts and filters secure connections. Products with this feature include Avast, BitDefender, Bullguard, ESET, and Kaspersky; AVG LinkScanner / SurfShield can cause this error on search sites.

(3) On Windows 10, Firefox not being set up to work with the parental control software Microsoft Family Safety. (To test by turning it off, see: http://windows.microsoft.com/en-us/wi.../turn-off-microsoft-family-settings)

(4) Malware on your system intercepting secure connections.

If you have any of those specific security products:

That would be the first thing to check. This support article will walk you through it: How to troubleshoot security error codes on secure websites.

If none of those ring a bell:

You could inspect a sample certificate to see whether that points to the culprit. If you want to try that now, here's how I suggest starting:

Load my test page at: https://jeffersonscher.com/res/jstest.php

You likely will get an error page. Expand the "Advanced" button 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.

Tried all of the above, so far nothing has worked. And, i do not have any of the blocking software. I have deleted Firefox and all the preferences. Re-started the computer downloaded a new Firefox and still get the same messages.

Could you try my test page and check the certificate details there as I described in my earlier post?

Thank you jscher2000. Do not know what did it but I followed your tips and also re-installed mac osx and now I am up and running. Thank You