Please re-install firefox by downloading fresh installer.

In terminal

apt-get install firefox

hello Saurav, the user's system details on the top left show that it's a question from linux.

philipp said

hello Saurav, the user's system details on the top left show that it's a question from linux.

Really sorry, i pasted wrong link.

Saurav said

Please re-install firefox by downloading fresh installer. In terminal apt-get install firefox

Hello i have this problem on both Linux(Fedora 20)(FF36.0.0) and windows 7(FF36.0.1). I re-install firefox on windows and there was no effect - problem remains.

1. Please check system dates and times.

Please follow this

https://support.mozilla.org/en-US/kb/connection-untrusted-error-message

The date and time is correct. The problem is that button "Add Exception..." not work ,when i click on it nothing happen.

Open this chrome URI by pasting or typing this URI in the location/address bar to open the "Add Security Exception" window and check the certificate:

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

In the location field type/paste the URL of the website

• retrieve the certificate via the "Get certificate" button
• inspect the certificate via the "View..." button

What does it show in the Technical details?

cor-el said

Open this chrome URI by pasting or typing this URI in the location/address bar to open the "Add Security Exception" window and check the certificate:

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

In the location field type/paste the URL of the website

• retrieve the certificate via the "Get certificate" button
• inspect the certificate via the "View..." button

What does it show in the Technical details?

Ok , i try this and show me the "no information Availible \n Unable to obtain identification status of this site"

By the way i get older version of FF(35.0) on windows and there the Untrusted pages open correct. It show me again the page "This Connection is Untrusted" ,but the button "Add Exception..." work and open the page.

My system date and time had changed and were way off. I entered the correct date and time and everything back to normal.