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"Did Not Connect: Potential Security Issue" on every sites

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  • Last reply by FredMcD

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Since yesterday I am getting this "Did Not Connect: Potential Security Issue" error on every sites that I have tried to visit. Even on well known secured sites like https://drive.google.com is inaccessible while my Chrome and Edge is working fine. Any solution?

Since yesterday I am getting this "Did Not Connect: Potential Security Issue" error on every sites that I have tried to visit. Even on well known secured sites like https://drive.google.com is inaccessible while my Chrome and Edge is working fine. Any solution?
Attached screenshots

Chosen solution

Hi FredMcD, Thanks for your response. Unfortunately none of these solution is working out for me. I don not use any third party antivirus or internet security software except for windows defender. However, finally turns out that turning on "Automatic proxy configuration URL" under Setting>Network setting solves the issue. I am not sure whether this will cause any security threat or other malfunction or not.

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  • MOZILLA_PKIX_ERROR_MITM_DETECTED
  • uses an invalid security certificate SSL_ERROR_BAD_CERT_DOMAIN
  • configured their website improperly

How to troubleshoot the error code "SEC_ERROR_UNKNOWN_ISSUER" on secure websites https://support.mozilla.org/en-US/kb/troubleshoot-SEC_ERROR_UNKNOWN_ISSUER


There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connection certificates and send their own.

https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites

https://support.mozilla.org/en-US/kb/secure-connection-failed-firefox-did-not-connect

https://support.mozilla.org/en-US/kb/websites-dont-load-troubleshoot-and-fix-errors

What do the security warning codes mean

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Chosen Solution

Hi FredMcD, Thanks for your response. Unfortunately none of these solution is working out for me. I don not use any third party antivirus or internet security software except for windows defender. However, finally turns out that turning on "Automatic proxy configuration URL" under Setting>Network setting solves the issue. I am not sure whether this will cause any security threat or other malfunction or not.

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You can check the connection settings.

  • Settings -> General -> Network: Connection -> Settings

If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.

See "Firefox connection settings":

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That was very good work. Well Done.