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certificate error

  • 5 replies
  • 284 have this problem
  • Last reply by talamortis

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When I go to one of our development sites, I get this error: Secure connection failed An error occurred during a connection to Peer's certificate has an invalid signature (Error code: sec_error_bad_signature) . I do not have the option to add an excpetion anymore, but we used to be able to navigate there. I'm running 3.6.13.

All Replies (5)

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I'm also using Firefox 3.6.13 and had the same problem. This issue can be solved simply by changing Firefox's configuration - it's NOT necessary to install any Firefox add-ons to do this, even though internet searches will list various add-ons for fixing this problem.

This is how it's done:

- Open a new Firefox window, and type this into the address/URL:


- You'll probably see a warning that changing the config can be dangerous. Click the button to accept the warning and proceed, but BE CAREFUL from here on!

- A table will appear showing various Firefox settings ("Preference Names") and their current values.

- In the Filter box type: broswer.xul

- There should now be a shorter list of settings, including one named browser.xul.error_pages.expert_bad_cert with a value of false.

- Right-click on browser.xul.error_pages.expert_bad_cert and select Toggle. The value will change to true.

- Exit completely from Firefox (i.e. close all windows), and then restart it.

The next time you visit a secure site where there is a problem with its certificate, the certificate error page will show a button that allows the site to be added as an exception, and then you'll be able to proceed and view the site.

WARNING: If Firefox warns that there is a problem with a site's certificate, proceed only if:

a) you are 100% certain that it's safe, or

b) you accept the risks!

Certificate warnings should definitely NOT appear on any sites dealing with money/transactions, e.g. online shopping, online banking, etc.

Hope this helps!


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This doesn't always seem to work. I still get the same error and there is no button to allow me to add this site as an exception I am using version 3.6.18 and followed these instructions carefully but the same error page described here comes up when I tried to access my https site.

Modified by pamjustice

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I am now using v3.6.18 as well. I have just tested this again, and it's working fine. I would suggest trying the following:

- Make sure every Firefox window has been closed

- Start Firefox in Safe Mode: Click Start -> Programs -> Mozilla Firefox -> Mozilla Firefox (Safe Mode)

- Go to about:config and ensure that the value of browser.xul.error_pages.expert_bad_cert is set to true, as described above

- Close the Firefox window and reboot your computer

- Start Firefox in Safe Mode again and check the setting of browser.xul.error_pages.expert_bad_cert - hopefully it will still be true

- Try opening the https page that you want to access and see if the button to add an exception is now available

- If that works, close the Firefox window, then restart Firefox normally (i.e. not in Safe Mode) and try the https page again

Hope that helps!


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Frustrating, tried all the above to no avail, but in the end after some searching found I had to import a versign certificate:

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Make sure your date and time is correct i had the same problem and thats how i fixed this