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Suddenly my Firefox is giving a Secure Connection Failed error.

Upon some googling from Chrome, I found that some settings/certificate issues in Kaspersky may cause this. So, I tried exiting Kaspersky Internet Security and Firefox works as usual.

I am using:

  • Windows 11 Version 22H2 (OS Build 22621.2070)
  • Firefox 116.0.1
  • Kaspersky Internet Security (K)

How can I fix the issue?




Screenshot 2023-08-07 122216.png


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Hello @Abhik B

As well as the above post.

Try this script.

The "PR_CONNECT_RESET_ERROR" in Firefox typically indicates that the browser was unable to establish a secure connection to the website you were trying to visit. This can be caused by various factors, including issues with your internet connection, browser settings, or security software like Kaspersky Internet Security.

Since you mentioned that the error occurs when using Kaspersky Internet Security, here are a few steps you can try to resolve the issue:

1. **Disable HTTPS Scanning**: Kaspersky Internet Security often includes a feature called "HTTPS scanning" or "SSL/TLS protocol filtering" that intercepts and scans encrypted connections. Sometimes, this feature can conflict with the browser's secure connections. Try disabling this feature in Kaspersky's settings and then restart your browser to see if the issue is resolved.

2. **Clear SSL State**: Sometimes, cached SSL certificates can cause connection issues. You can try clearing the SSL state in Firefox by following these steps:
   - Open Firefox.
   - Go to the menu (three horizontal lines in the upper-right corner) and select "Options."
   - In the left sidebar, click on "Privacy & Security."
   - Scroll down to the "Certificates" section and click on "Clear Site Data..."
   - Check the box next to "Active Logins" and "Cache" and click "Clear."

3. **Check Proxy Settings**: Make sure that your browser is not configured to use a proxy server that might interfere with the connection. In Firefox, you can check this by going to "Options" > "General" > "Network Settings."

4. **Update Kaspersky and Firefox**: Ensure that both Kaspersky Internet Security and Firefox are up to date. Outdated software can sometimes lead to compatibility issues.

5. **Try Another Browser**: If the issue persists, try accessing the website in a different browser (e.g., Chrome, Edge) to see if the problem is specific to Firefox.

6. **Temporary Disable Kaspersky**: As a test, you can temporarily disable Kaspersky Internet Security and see if the issue goes away. If it does, then it's likely that some setting or feature in Kaspersky is causing the problem.

7. **Contact Support**: If none of the above steps resolve the issue, you may want to reach out to Kaspersky's support or Firefox support for further assistance. They might have specific recommendations based on your setup.

Remember that adjusting security settings can have implications for your computer's safety, so make sure you're aware of the potential risks and only make changes if you are comfortable doing so.

Thank you

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  • 7 months later...

Thanks KarDip.  A very helpful well-written set of suggestions.

In my case,  I encountered this PR_CONNECT_RESET_ERROR  when using Firefox fairly tightly locked down,   ( I already use DNS over HTTPS  and specifically defined DNS servers).  The problem occurred after a Firefox update.  My problem turned out to be "Kaspersky intercepts and scans encrypted connections."  as turning off  "Encrypted connection scanning" in Kaspersky.  At least this appears to solve the problem.

I'm guessing Firefox slightly changed the way DNS over HTTPS  is done, and it didn't match Kaspersky's checking.

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  • 2 weeks later...


Greetings to all. It happens to me exactly the same. I am in the hands of Kaspersky professionals via email. In my case it only happens with one domain in question.

Even with a fresh reinstall of Windows. Nothing seems to work. Just stop the protection and close the application completely from the tray. Just stopping the protection doesn't work either and it's still blocked.

It doesn't matter whether you use Kaspersky Internet Security or Kasperky Standard. It also doesn't matter if it's on Windows 10 or 11. Neither does Firefox or Edge. You can see the attached photos.

As soon as they find the solution to my problem I will post it to the community.

Thank you.

Error KIS (1).png

Error KIS (2).png

Error KIS (3).png

Error KIS (4).png

Error KIS (5).png

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Yes. Furthermore, on computers where I do not have any Kaspersky solution installed, the problem does not occur. In fact, with my cell phone I can enter without problems.

Thank you.

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Don't worry, I'm currently in the hands of the experts at Kaspersky. I just sent the person handling my case a report with WireShark and Kaspersky Traces. I think they are close to finding the problem. When this is the case I will inform you. So that the entire community benefits. All the best.

  • Like 2
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  • 2 weeks later...

I have the same problem.

Just updated Windows and now my Firefox is no longer working. Chrome works fine, Edge works fine.

I get this however in Firefox, no matter which site I visit.


Secure Connection Failed

An error occurred during a connection to www.google.com. PR_CONNECT_RESET_ERROR


I've tried everything listed above.

Please assist.

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3 hours ago, Deformiter said:

I have the same problem.
Just updated Windows and now my Firefox is no longer working. Chrome works fine, Edge works fine.
I get this however in Firefox, no matter which site I visit.
I've tried everything listed above.

4. Please assist.

Hello @Deformiter


Read & follow this guide:  Read before you create a new topic OR update an existing topic!

  1. Updated Windows from what to what?
  2. Kaspersky software name & version is? 
  3. Firefox version is? 
  4. Log a request with Kaspersky Customer Service, https://support.kaspersky.com/b2c#contacts - on the support page, select either Chat or Email, then fill in template as shown in the image below; please include any screen images of the error & a *detailed history*. Support may request logs, traces & other data; they will guide you:


Please share the outcome with the Community, when it's available? 
Thank you🙏

Edited by Flood and Flood's wife
Updated 3. Added resource
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