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Unable to go to Mozilla or Firefox websites

  • 9 respostas
  • 5 have this problem
  • 4 views
  • Last reply by Punt

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I just installed Firefox on my work laptop, and imagine my surprise when the very first website I try to visit, the https://accounts.firefox.com site, won't open because:

accounts.firefox.com uses an invalid security certificate. The certificate is not trusted because the issuer certificate is unknown. (Error code: sec_error_unknown_issuer)

This also happens with support.mozilla.org, and pretty much every https site I try.

I've looked for solutions and the best anyone can say is "delete the cert8.db" file... which doesn't help.

I have deleted cert8.db twice, and reset Firefox. Nothing I've done has worked. And the pages all open fine using other browsers.

How do I fix this? Or do I give up on Firefox within 10 minutes of trying it...?

I just installed Firefox on my work laptop, and imagine my surprise when the very first website I try to visit, the https://accounts.firefox.com site, won't open because: accounts.firefox.com uses an invalid security certificate. The certificate is not trusted because the issuer certificate is unknown. (Error code: sec_error_unknown_issuer) This also happens with support.mozilla.org, and pretty much every https site I try. I've looked for solutions and the best anyone can say is "delete the cert8.db" file... which doesn't help. I have deleted cert8.db twice, and reset Firefox. Nothing I've done has worked. And the pages all open fine using other browsers. How do I fix this? Or do I give up on Firefox within 10 minutes of trying it...?

Chosen solution

Thanks Phillip, I managed to export the certificates from Chrome, and then import them to Firefox. So it seems to be working, more or less (Sync is not working so well but that could be unrelated).

Thanks for all your help though, really appreciate it!

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All Replies (9)

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hello, a possible solution depends on different factors. please attempt to add an exception on the bottom of the error page & inspect the certificate (see the screenshot attached for instructions):

  • which issuer information does the certificate contain?

thank you!

"This Connection is Untrusted" error message appears - What to do

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Is the day, date, and time set correctly in Windows?

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Hi Phillip. It's a Mozilla/Firefox certificate so will that tell you the issuer information? I am not given the option to add an exception, so I don't know how to view the certificate (there is no View option; see attachment).

Hi the-edmeister. The date and time are set automatically on our systems, but I have never had a problem with certificates on other browsers. I say that because I assume if it's a problem with the system date or time, it would affect the certificates for all browsers.

One thing we do have is McAfee running. Again, this hasn't affected other browsers. But I did see reports of anti-virus interfering with Firefox on https...

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is there an "add exception" button on other sites like https://support.mozilla.org?

philipp modificouno o

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On the support.mozilla.org yes, I see now the certificate is issues by Zscaler Intermediate Root CA.

It is valid from 18/09/2013 to 23/09/2015

On other sites, like Gmail, I don't have the option to add an extension.

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hello, zscaler seems to be another legitimate security product running on your work laptop - probably inspecting the network traffic, which might look like a man-in-the-middle attack for firefox. you'll have to install the zscaler root certificate into firefox, so that it will be treated as a trusted instance. unfortunately i've found no publicly available certificates by zscaler, so you might have to contact the admin responsible for the work machine to help you out here...

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Thanks so much, I've also sent zscaler an email (doubt I'll get a positive response though).

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this site appears to publicly host the zscaler root certificate for installation: http://www.orange.k12.nc.us/staff/staff_zscaler.html

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Chosen Solution

Thanks Phillip, I managed to export the certificates from Chrome, and then import them to Firefox. So it seems to be working, more or less (Sync is not working so well but that could be unrelated).

Thanks for all your help though, really appreciate it!