Did you come to the Mozilla website for the update?

Please explain the problem in detail. What happens? What is/are the exact error message(s) ?

Hi Roy, is this problem only on one site?

Generally speaking, Firefox would give an expired certificate message if the site presents Firefox a certificate that is no longer valid on your current system date. So if a lot of sites are affected, this sometimes indicates that your system clock got set to a date far in the future or the past.

Normally you would not need to delete any saved certificates in Firefox, but if that is the problem, you can search for that old certificate through the Options page as follows:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the search box at the top of the page, type cert and Firefox should filter to the relevant section. Click the "View Certificates" button to open the Certificate Manager.

This dialog has several sections: click the Servers in the top row.

Can you find a certificate for the site listed there? If so, you can select it and click the Delete button to remove it.

If you don't find it, don't worry, that's normal, then the problem is with the current site certificate or with your system clock.

Hi jscher2000 Sadly the problem has re appeared I have re checked the certificats as you suggested and have have found a number of referencies to COMODO RSA certificates under the authorites tab but they seem to be well in date When I view the Cert on the security alert it expired in 2019 the problen only appears on 1 web site ( marine traffic com)

Regards Roy