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FireFox is blocking many sites and says This Connection is Untrusted

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many sites is blocked by firefox like facebook , yahoo mail and even this site. its saying This Connection is Untrusted and this sites working on other browsers and i'm sure that the pc date is right and up to date so what???

many sites is blocked by firefox like facebook , yahoo mail and even this site. its saying This Connection is Untrusted and this sites working on other browsers and i'm sure that the pc date is right and up to date so what???

Chosen solution

Which security software (firewall, anti-virus) do you have?

Some monitor secure connections and send their own certificate instead.

Some examples:

  • ESET setup -> advanced setup -> extend web and email tree -> SSL
  • SSL protocol: Do not scan SSL protocol
  • BitDefender -> Privacy settings -> disable Scan SSL
Read this answer in context 👍 7

All Replies (15)

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Chosen Solution

Which security software (firewall, anti-virus) do you have?

Some monitor secure connections and send their own certificate instead.

Some examples:

  • ESET setup -> advanced setup -> extend web and email tree -> SSL
  • SSL protocol: Do not scan SSL protocol
  • BitDefender -> Privacy settings -> disable Scan SSL
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tnx man it's working good now thank you

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You're welcome

Which security software do you have?

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Hi am not clear on the instruction: SSL protocol: Do not scan SSL protocol do I select that function or deselect it. Am having hell after reset and troubleshooting I cannot access any site without the Untrusted message coming up ..I use eset

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"Do not scan SSL protocol" in the ESET options should be selected when you're having issues with the "This Connection is Untrusted"-error message showing up on any secure page.

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Am still having the problem even though I selected it. Thank you for quick response

Modified by toffa

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maybe it will take a restart of the pc for the settings to take effect. if this doesn't work either, could you look under "technical details" on the error page & tell us which error code is being displayed there?

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(Error code: sec_error_untrusted_cert) this is what am getting as an error in technical details

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ok, then the problem is likely caused by something else here (i think in the cases where ESET SSl scanning interfered sec_error_reused_issuer_and_serial would be shown).

please try this: go to firefox > help > troubleshooting information and open the profile directory (then close firefox). in the profile folder rename the files cert_override.txt & cert8.db to something like oldcert or delete them... afterwards restart the browser (this will regenerate the file in question again).

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Hi I tried it not happening. Ok am having trouble just getting into twitter, i can do my facebook, yahoo etc..its just strange as I was on twitter earlier today..

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this seems strange - can other browsers on your pc display those secure sites without any error messages?

another thing you could try in firefox is to create a new profile & see if this works...

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Yes am able to open twitter on IE with no problem at all..Thanks

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Some firewalls monitor secure (https) connections and send their own certificate instead of the website's certificate.

You can retrieve the certificate and check details like who issued certificates and expiration dates of certificates.

  • Click the link at the bottom of the error page: "I Understand the Risks"

Let Firefox retrieve the certificate: "Add Exception" -> "Get Certificate".

  • Click the "View..." button and inspect the certificate and check who is the issuer.

You can see more Details like intermediate certificates that are used in the Details pane.

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Hi Thanks, managed to get it going. Much appreciated.

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I have been having the same problem, chased my tail around for ages and then realised that my system clock was out of date because my laptop battery is toast.

I reset my clock to today's date and the certificate errors disappeared.

Check your clock?