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clear cache completely in Kubunu

  • 3 replies
  • 1 has this problem
  • 34 views
  • Last reply by nula

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After creating a new virtual website with a letsencrypt certificate there was an error. This error is fixed. The certificate is valid and checked. When I go to the website, I get no errors. But Firefox does not load the css-files from a subdirectory. I go to the source of the page, click on the css-file : nothing happens. I copy the link location and paste it in a new tab. I get the errors: "Warning: Potential Security Risk Ahead" "Error code: SSL_ERROR_BAD_CERT_DOMAIN" It seems, that Firefox remembers, that there was a problem. But this problem is solved. Accoring to ssllabs.com/ssltest/analyze.html the certificate is valid. Chrome thinks the certificate is valid. Firefox thinks the certificate is valid, but not for a css subdirectory.

I cleared the cache of firefox with 'privacy and security -> clear data'.

'Privacy and security -> clear history when firedox closes' is set with all settings enabled, including 'Offline website data'. After restarting Firefox the error is the same. Is this a bug or do I overlook something ?

After creating a new virtual website with a letsencrypt certificate there was an error. This error is fixed. The certificate is valid and checked. When I go to the website, I get no errors. But Firefox does not load the css-files from a subdirectory. I go to the source of the page, click on the css-file : nothing happens. I copy the link location and paste it in a new tab. I get the errors: "Warning: Potential Security Risk Ahead" "Error code: SSL_ERROR_BAD_CERT_DOMAIN" It seems, that Firefox remembers, that there was a problem. But this problem is solved. Accoring to ssllabs.com/ssltest/analyze.html the certificate is valid. Chrome thinks the certificate is valid. Firefox thinks the certificate is valid, but not for a css subdirectory. I cleared the cache of firefox with 'privacy and security -> clear data'. 'Privacy and security -> clear history when firedox closes' is set with all settings enabled, including 'Offline website data'. After restarting Firefox the error is the same. Is this a bug or do I overlook something ?

Chosen solution

Hello nula,

Follow the instructions and step :


1. Continue With an Insecure Connection Some errors will allow you to accept the risk and continue. You can continue with the insecure connection at your own risk:

  • Click on Advanced.
  • Click on Accept the Risk and Continue.

Note: This trick will not work for the “SEC_ERROR_REVOKED_CERTIFICATE” and other sort of serious errors. If you don’t see this option, move on to the next solution.

2. Add the Site to Your List of Trusted Sites Search for Internet Options in the Windows search bar.


  • Search for Internet Options in the Windows search bar.
  • In the pop-up window, click on the Security tab.

Select Trusted sites.

Click on the Sites button to open a new window.

  • Manually add the URL of the website that is displaying the error message.
  • Click Apply and OK.

3. Temporarily Disable Your Antivirus and Firewall

Some antivirus and firewall solutions are sensitive to SSL errors. To address this issue, all you need to do is turn off HTTPS scanning. All antiviruses have different SSL scanning under different names. Find the appropriate setting such as “HTTPS Scanning,” “Scan SSL”, “show safe result,” “Do not scan encrypted connections,” etc.,and disable it.

If you don’t see any such options, visit the manufacturer’s help section and try to find SSL- and HTTPS-related settings information there.

4. Clear the SSL State

  • Search for Internet Options in the Windows search bar.
  • In the pop-up window, select the Content tab.
  • Click on Clear SSL State to clear your SSL cache.


5. Clear Your Browsing History

  • Open Firefox and navigate to Options in the top-right drop-down menu.
  • Go to Privacy and Security from the menu bar on the left side.
  • Click on Clear Data in the Cookies and Site Data section.
  • Select Clear History.
  • Select all the options and click on Clear Now.


6. Permit Firefox to Trust Root Authorities Firefox has an optional feature that allows the browser to trust root authorities in the Windows certificate store. To activate this feature, you must enable the setting in your browser.

Fix the ‘Warning: Potential Security Risk Ahead’ Error in Firefox

Type “about: config” into the Firefox address bar.

Press the I accept the risk! button.

Search for security.enterprise_roots.enabled. Fix the ‘Warning: Potential Security Risk Ahead’ Error in Firefox In the security.enterprise_roots.enabled window, look to the right side of the screen. If the value is False, double-click on it. The value will get changed to True.

Restart Firefox. If you still see the error message, move to the next solution.

  • save all changed

Finally restart you computer.



I hope resolve your problem then reply me


Thank you

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All Replies (3)

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Click the menu button. and select Options. ... Select the Privacy & Security panel. In the Cookies and Site Data section, click Clear Data…. Remove the check mark in front of Cookies and Site Data. ... With Cached Web Content check marked, click the Clear button. Close the about:preferences page.

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Chosen Solution

Hello nula,

Follow the instructions and step :


1. Continue With an Insecure Connection Some errors will allow you to accept the risk and continue. You can continue with the insecure connection at your own risk:

  • Click on Advanced.
  • Click on Accept the Risk and Continue.

Note: This trick will not work for the “SEC_ERROR_REVOKED_CERTIFICATE” and other sort of serious errors. If you don’t see this option, move on to the next solution.

2. Add the Site to Your List of Trusted Sites Search for Internet Options in the Windows search bar.


  • Search for Internet Options in the Windows search bar.
  • In the pop-up window, click on the Security tab.

Select Trusted sites.

Click on the Sites button to open a new window.

  • Manually add the URL of the website that is displaying the error message.
  • Click Apply and OK.

3. Temporarily Disable Your Antivirus and Firewall

Some antivirus and firewall solutions are sensitive to SSL errors. To address this issue, all you need to do is turn off HTTPS scanning. All antiviruses have different SSL scanning under different names. Find the appropriate setting such as “HTTPS Scanning,” “Scan SSL”, “show safe result,” “Do not scan encrypted connections,” etc.,and disable it.

If you don’t see any such options, visit the manufacturer’s help section and try to find SSL- and HTTPS-related settings information there.

4. Clear the SSL State

  • Search for Internet Options in the Windows search bar.
  • In the pop-up window, select the Content tab.
  • Click on Clear SSL State to clear your SSL cache.


5. Clear Your Browsing History

  • Open Firefox and navigate to Options in the top-right drop-down menu.
  • Go to Privacy and Security from the menu bar on the left side.
  • Click on Clear Data in the Cookies and Site Data section.
  • Select Clear History.
  • Select all the options and click on Clear Now.


6. Permit Firefox to Trust Root Authorities Firefox has an optional feature that allows the browser to trust root authorities in the Windows certificate store. To activate this feature, you must enable the setting in your browser.

Fix the ‘Warning: Potential Security Risk Ahead’ Error in Firefox

Type “about: config” into the Firefox address bar.

Press the I accept the risk! button.

Search for security.enterprise_roots.enabled. Fix the ‘Warning: Potential Security Risk Ahead’ Error in Firefox In the security.enterprise_roots.enabled window, look to the right side of the screen. If the value is False, double-click on it. The value will get changed to True.

Restart Firefox. If you still see the error message, move to the next solution.

  • save all changed

Finally restart you computer.



I hope resolve your problem then reply me


Thank you

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Thank you for your answers. Accepting the security risk worked. Most of the suggestions seem to be for windows, I work with kubuntu linux. In kubuntu 14 there were no problems. Last week I upgraded to kubuntu 20 with the latest version of Firefox. I am not very happy with the new version.