Firefox Community Forum

When following a link from a news website I keep getting this message - Secure Connection Failed - The page you are trying to view cannot be shown because the authenticity of the received data could not be verified. It loads on my iPhone and other browsers using the same link. What setting do I need to address to get this to stop?

I'm reposting a question already opened here because a moderator suggested to do so. Actually I though I was posting to the international forum from the URL...

I was trying to access a local HTTPS website of an embedded device (a Siemens S7-1500 PLC) that is using a self-signed certificate, but was unable to go on (attached image #1, in Italian language) due to the the SEC_ERROR_REUSED_ISSUER_AND_SERIAL error. I've browsed a similar PLC webserver in the past, so the fact that the device exposes a similar certificate serial number is not so strange for me, considering also it's self-signed.

The problem is that I cannot follow the instructions of the Mozilla knowledgebase here because I'm not able to identify the correct certificate of the website!

In the attached image #2 you can see that the connection is detected as not encrypted, I suppose because only the form part of the HTML that is posting the data using HTTPS while the rest is using HTTP, but I'm not sure. If I click on the padlock icon (attached image #3) the info about the current certificate is not displayed.

Then I went into Tools > Options and searched for "certificates"; as you can see in the attached images #4 and #5, neither in the Servers tab nor in the Authorities tab I can find any item that is related to 192.168.10.2 (the webserver IP address) or Siemens (the embedded device manufacturer). But unfortunately the error persist! Initially there was a 192.168.10.2:443 line in the Servers tab and I removed it and restarted Firefox, but it didn't solve, so at the moment the situation is the one depicted by the attachments.

I had to use Microsoft Edge to access the website, but I would like to solve this issue and use Firefox instead. Is there anything else I can do to bypass the error? Why doesn't the error page provide a way to correctly identify the wrong certificate using its fingerprint and/or name? Or, maybe, is there a way to disable this check for local IP addresses or for items in a whitelist?

Thanks for your help.

Be careful. Something doesn’t look right.

Firefox spotted a potentially serious security issue with www.aol.fr. Someone pretending to be the site could try to steal things like credit card info, passwords, or emails. ??????? I used Aol since 1998 !!!!!!!!

Give me back my access to irccloud.com. I have been using that website for over 5 years on FireFox and then this morning you denied me access. Thanks for checking and correcting.

My laser printer will not print due to low toner. However, when I click on "more information" to find out the toner level, that site is shown as unsecure and cannot be accessed.

12 hours ago Firefox stopped working .No reason ; no changes just the following message including access to this site.So now I have to access with edge . Secure Connection Failed

The page you are trying to view cannot be shown because the authenticity of the received data could not be verified. What can you do about it?

The issue is most likely with the website, and there is nothing you can do to resolve it. You can notify the website’s administrator about the problem.

I was browsing for vacant jobs in LinkedIn and ended up on this page: https://www.linkedin.com/jobs/view/4400116024/?trackingId=&refId=&midToken=AQHkKqfITpiwdw&midSig=2f8JsuceFtMYc1&trk=eml-email_jobs_application_rejected_01-similar_jobs-0-similar_job&trkEmail=eml-email_jobs_application_rejected_01-similar_jobs-0-similar_job-null-g3nlj~mo2hn6z8~of-null-null&eid=g3nlj-mo2hn6z8-of&otpToken=MTAwMjFlZTQxNjJhYzljM2JlMmYwMmVkNDAxYWU3YjA4NmNiZDQ0MzlkYWQ4NTZjNzljMTAxNjg0ZjU4NWZmM2YzZGZiN2JjNTVjNWZjZTc3YjhmZDg3ZWQ5YTExZWUyMDg1N2Q1YzI4OGNjNDU0MjU3YTEsMSwx But pressing the Apply button, did not take me to the application page, but instead a page that was saying: "Be careful. Something doesn’t look right. Firefox spotted a potentially serious security issue with jobs.tuvsud.com. Someone pretending to be the site could try to steal things like credit card info, passwords, or emails." And there was no option to ignore this and just go to the site??? I needed to open MS Edge instead, to be able to apply for the job???

Why does my older computer running Windows 7 keep losing the ability to access "https:// sites"?

To resolve, I have to reset the network adapter (sometimes successful) or restart the computer to access these sites.

In this case I accessed my Acer account and clicked on my notebook. I then got the screen shown in the image. I could access the page with Opera, Chrome, and Edge.

This is happening a lot, and is rendering Firefox unusable as my default browser.

Current Setup: OS: Windows 11 Home (10.0.26200) Firefox Version: 151.0.2 (Build ID: 20260525130955)

Issue:

• Firefox suddenly is unable to connect to any wesbite
• All attempts to browse result in the "Secure Connection Failed" screen
• All other browsers function fine with no network connectivity issues

Exact Display Text:

Secure Connection Failed

The page you are trying to view cannot be shown because the authenticity of the received data could not be verified. What can you do about it?

The issue is most likely with the website, and there is nothing you can do to resolve it. You can notify the website’s administrator about the problem.

Attempted Fixes / Things Confirmed:

• Everything mentioned in: Firefox can't load websites but other browsers can

• Relevant about:config values:

* * security.enterprise_roots.enabled -> True

• * security.ssl.enable_ocsp_must_staple -> True
• * security.ssl.enable_ocsp_stapling -> True
• * security.tls.version.max -> 4
• * security.tls.version.min -> 3

• System locale and timezone are correct
• DNS over HTTPS is set to OFF
• HTTPS-Only Mode is set to Don't enable HTTPS-Only Mode
• Restarting in Troubleshooting Mode
• Disabling the Anti-Virus (including the device Firewall)
• Disabling any VPNs or network proxies
• Clearing cache and browsing history
• Clearing certificates from the Certificate Manager in Settings
• Attempting connection with a newly created profile
• Clearing the cert9.db file for Firefox to reset certificate information
• Refreshing Firefox (resetting it completely)
• Uninstalling and reinstalling Firefox (after clearing all Mozilla related %appdata% folders)

Observations

• When trying to mess with the device timezone and see if changing it back to the correct one would "reset" something, after a few attempts of starting Firefox in the wrong timezone and then restarting it after changing to the correct one, for a single session, I was able to browse normally again. I closed Firefox to see if the problem was fixed but it went back to the "Secure Connection Failed" page. Was unable to reproduce the same behavior.

• Tried installing a portable version of Firefox (151.0.3) from Firefox Portable .

After installation, the first session works perfectly fine but after I close the session and restart Firefox, it gives the same "Secure Connection Failed" message.

• * Reinstalling the portable version in the folder, gives the error from the get-go, not even the initial post-installation session works but installing in a different folder works fine for the first session but all subsequent restarts (sessions) of the browser give the same error.

This is my website I work on daily - I can normally open it in this browser BUT because Im on my laptop it is flagged as a security risk - and its not - passive-income-system[.]co[.]uk

Beginning today, I suddenly cannot access numerous websites when I use Mozilla Firefox 151.0.2. Examples include Amazon, and Google, et al. Attempts to do so consistently fail at the point of performing a TLS handshake, when I am advised that "secure connection failed". Kindly refer to the attached screenshots. I have no difficulty whatsoever accessing the same websites when I use other browsers, such as Google Chrome and MS Edge. I previously had Mozilla Firefox enabled as my default browser, but I have had to change this, given these "challenges". Please advise how I can fix this. Best regards and many thanks.

Firefox detected a potential security threat and did not continue to apps.ngte-welfaretrust.gov.bd because this website requires a secure connection.

What can you do about it?

apps.ngte-welfaretrust.gov.bd has a security policy called HTTP Strict Transport Security (HSTS), which means that Firefox can only connect to it securely. You can’t add an exception to visit this site.

The issue is most likely with the website, and there is nothing you can do to resolve it.

If you are on a corporate network or using antivirus software, you can reach out to the support teams for assistance. You can also notify the website’s administrator about the problem.

I have been having issues where I am unable to access the website: www.loki.ch. This is the web site for a Swiss railway magazine. I have always been able to access it previously, but haven't used it now for a few months. However this week when I've tried, I'm blocked access to it (see the attached screen shots). I do note that since I had previously access the web site, there have been updates to Firefox. However, when trying to use either Edge or Google Chrome, they also block me, but just say that unable to access the web site, nothing mentioned about being "Not Secure" as Firefox does. It's not a web site where you have to log in and/or use passwords. Contacting the magazine by Facebook messenger yields no response from them. Posting the issue on a Facebook group, other users have responded that they can access it (one was from Slovenia and the other in the UK). One mentioned issues from Australia where I am. It's not a dangerous or suspect web site, simply a magazine about Swiss Model Trains. I have tried adjusting settings to exempt it in Settings - no change. Not a anti virus issue. None of the suggestions in the FAQ have exactly the same scenario in the screen shots attached.

Surely there has to be some way to bypass whatever is in Firefox Security preventing me from accessing this web site?

If I try to log into my router at 192.168.1.1 I get a message that says "Warning: Potential Security Risk Ahead". I expect that, but when I click on the Advanced button it doesn't do anything. Works fine with Chrome, so not my router or anti-virus. ???

Windows 10 Firefox 148.0

I am trying to access certain HTTPS website and some of them show PR_CONNECT_RESET_ERROR in Firefox. This error is not present in Edge or Chrome. Any ideas on what could be the problem?

An error occurred during a connection to delta-executorr.com. PR_CONNECT_RESET_ERROR

Error code: PR_CONNECT_RESET_ERROR The page you are trying to view cannot be shown because the authenticity of the received data could not be verified. Please contact the website owners to inform them of this problem.

Here's what I've tried (none of these works):

   DNS over HTTPS turned off
   Uninstall all add-ons
   Reinstall Firefox
   Create new profile and set it as default
   Delete/rename certs.db in the Firefox profiles folder. 

I'm tired fixing errors which become more complex and solutions are written for people who have the time an knowledge to waste fixing these constant issues in FIREFOX, Time to change browser.

I don't know if this is relevant but one of the website that does not work is https://delta-executorr.com/

I am running windows 11. I routinely use firefox to access wireclub.com. Two days ago I started getting the following error:

We encountered a problem when completing your request.

We have been notified and are attempting to fix the problem as quickly as possible.

Invalid SSL certificate

The origin web server does not have a valid SSL certificate.

   Ray ID: 9eee0086ced8439d
   Your IP address: 2600:4041:59b2:8c00:c9fa:28ce:b4cb:4bfc
   Error reference number: 526
   Cloudflare Location: Newark

I tried clearing my cache that did not work. All other sites other than wireclub.com are working fine. I can access wireclub.com with Microsoft edge no problem. Any suggestions

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