Firefox Community Forum

Warning: Potential Security Risk Ahead

Firefox detected a potential security threat and did not continue to na.nikken.com. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details.

What can you do about it?

Probably nothing, since it’s likely there’s a problem with the site itself.

The site is ok when I open on another window and even on Google which I don't like.

I am new to firefox customization. I need help to understand, how firefox picks up CA certificates from the global ca-certificates path in ubuntu and uses them in their own cert9.db

Currently, what I am trying is, If I have a rootCA certificate (which I generated using openssl), I want to keep it in a specific path, such that when firefox launches, it picks up that certificate and uses it. How can i achieve it.

I have tried using the policies.json, which works. But are there any other ways to achieve it?

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.

How long before Nightly download site is available again?

https://download.mozilla.org/?product=firefox-nightly-latest-ssl&os=linux64&lang=en-US returns:

Did Not Connect: Potential Security Issue

Nightly detected a potential security threat and did not continue to download.mozilla.org because this website requires a secure connection.

What can you do about it?

download.mozilla.org has a security policy called HTTP Strict Transport Security (HSTS), which means that Nightly 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. You can notify the website’s administrator about the problem.

Learn more… Websites prove their identity via certificates. Nightly does not trust this site because it uses a certificate that is not valid for download.mozilla.org. The certificate is only valid for the following names: *.bbcollab.cloud, bbcollab.cloud

Error code: SSL_ERROR_BAD_CERT_DOMAIN

In the last few months, FireFox (accesed from Roamnia, on Firefox an a MacOS 26, both always updated to the latest available final version) has been showing the error: “Be careful. Something doesn’t look right. Firefox spotted a potentially serious security issue with e360.yale.edu. Someone pretending to be the site could try to steal things like credit card info, passwords, or emails. Advanced What makes the site look dangerous? Sites use certificates issued by a certificate authority to prove they’re really who they say they are. Firefox doesn’t trust this site because it looks like the certificate expired on 14/08/2026. What can you do about it? Your device’s clock is set to 22/09/2026. If this is correct, the security issue is probably with the site itself. If it’s wrong, you can change it in your device’s system settings. View the site’s certificate Learn more about troubleshooting time-related errors Error Code: SEC_ERROR_EXPIRED_CERTIFICATE 22 Sept 2026 08:34:11 EEST“ On perfectly innocent sites. Two examples: FAIR.org does not load beyond the initial “Home” page; e360.yale.edu/ shows the warning instead of accessing the homepage. This is annying, possibly wrong and, as any false security warning, potentially dangerous. Please help.

Hi,

I saw some forums and even google is blocked and i have this problems. I paste here the problem but my browser is en french:

'Connexion bloquée : problème de sécurité potentiel

Firefox a détecté une menace potentielle de sécurité et a interrompu le chargement de pasarela.clave.gob.es, car ce site web nécessite une connexion sécurisée.

Que pouvez-vous faire ?

pasarela.clave.gob.es a recours à une stratégie de sécurité HTTP Strict Transport Security (HSTS), une connexion sécurisée est obligatoire pour y accéder. Vous ne pouvez pas ajouter d’exception pour visiter ce site.

Le problème vient probablement du site web, donc vous ne pouvez pas y remédier.

Si vous naviguez sur un réseau d’entreprise ou si vous utilisez un antivirus, vous pouvez contacter les équipes d’assistance pour obtenir de l’aide. Vous pouvez également signaler le problème aux personnes qui administrent le site web.'

Any ideas ? how is possible that this website is giving me error? is a government one. Is something wrong with the certificate ?

https://pasarela.clave.gob.es/Proxy2/ServiceProvider

L’autorité de délivrance du certificat du pair n’est pas reconnue.

HTTP Strict Transport Security : false HTTP Public Key Pinning : false

Chaîne de certificat :

MIIHaDCCBlCgAwIBAgIQWpqJEEocRhJmJ4vag0L1lTANBgkqhkiG9w0BAQsFADBH MQswCQYDVQQGEwJFUzERMA8GA1UECgwIRk5NVC1SQ00xJTAjBgNVBAsMHEFDIENv bXBvbmVudGVzIEluZm9ybcOhdGljb3MwHhcNMjQwNDIzMTAyMjE4WhcNMjUwNDIz MTAyMjE4WjCBpjELMAkGA1UEBhMCRVMxDzANBgNVBAcMBk1BRFJJRDE/MD0GA1UE Cgw2TUlOSVNURVJJTyBERSBUUkFOU0ZPUk1BQ0lPTiBESUdJVEFMIFkgRlVOQ0lP TiBQVUJMSUNBMRIwEAYDVQQFEwlTMjgwMTUwMkIxGDAWBgNVBGEMD1ZBVEVTLVMy ODAxNTAyQjEXMBUGA1UEAwwOKi5jbGF2ZS5nb2IuZXMwggEiMA0GCSqGSIb3DQEB AQUAA4IBDwAwggEKAoIBAQDcaQKh6E0M2bug2X8xGrnYFyXMBbdc3ooYasMjBxqH rnoj1bsIu1GoByNc4CtYsocWQ20GygYT9Q1ko+8xwQvhsaNe0dTDM3Tjn5GZCH1S kYP5px2T2Z8a+1itnH2XJMepMyRc1KUAI95K37Dv+nV0L07befk61L6aLKOlr33k OGQQTwEJst2mdPjepALpNrHEHnVnkzc1sUACmbLaPhQPdizEdcZ7n8q5FlcncTgV JEANqdlgWm9pEPNCzr1hIJy9XQ506PJf1ZZgRmlgqXSutjxQqhr13m7incqhhqPf ZCbFgM+B8k/zc/AGs7Rcro4s2bEoBsQ2bth4PP8r5K5zAgMBAAGjggPuMIID6jAM BgNVHRMBAf8EAjAAMIGBBggrBgEFBQcBAQR1MHMwOwYIKwYBBQUHMAGGL2h0dHA6 Ly9vY3NwY29tcC5jZXJ0LmZubXQuZXMvb2NzcC9PY3NwUmVzcG9uZGVyMDQGCCsG AQUFBzAChihodHRwOi8vd3d3LmNlcnQuZm5tdC5lcy9jZXJ0cy9BQ0NPTVAuY3J0 MFgGA1UdIARRME8wCAYGZ4EMAQICMDkGCisGAQQBrGYDCREwKzApBggrBgEFBQcC ARYdaHR0cDovL3d3dy5jZXJ0LmZubXQuZXMvZHBjcy8wCAYGBACPegEHMCcGA1Ud EQQgMB6CDiouY2xhdmUuZ29iLmVzggxjbGF2ZS5nb2IuZXMwHQYDVR0lBBYwFAYI KwYBBQUHAwEGCCsGAQUFBwMCMA4GA1UdDwEB/wQEAwIFoDAdBgNVHQ4EFgQUeiO7 l/lXx1yzksu3IpvYH4q29zkwgaYGCCsGAQUFBwEDBIGZMIGWMAsGBgQAjkYBAwIB DzATBgYEAI5GAQYwCQYHBACORgEGAzByBgYEAI5GAQUwaDAyFixodHRwczovL3d3 dy5jZXJ0LmZubXQuZXMvcGRzL1BEU19DT01QX2VzLnBkZhMCZXMwMhYsaHR0cHM6 Ly93d3cuY2VydC5mbm10LmVzL3Bkcy9QRFNfQ09NUF9lbi5wZGYTAmVuMB8GA1Ud IwQYMBaAFBn4WC8U1qbMmwSYCA1M16sAp4NlMDoGA1UdHwQzMDEwL6AtoCuGKWh0 dHA6Ly93d3cuY2VydC5mbm10LmVzL2NybHNjb21wL0NSTDIuY3JsMIIBfQYKKwYB BAHWeQIEAgSCAW0EggFpAWcAdwBOdaMnXJoQwzhbbNTfP1LrHfDgjhuNacCx+mSx Ypo53wAAAY8Kek+TAAAEAwBIMEYCIQCtwlyMnKwLTwIEfZHv0LapvURkqsfdiOAK lqavldiQdQIhAKUw355ON4Qb/1HMH462bEqJyNfYc9a9QpeizZzr63CnAHUAzxFW 7tUufK/zh1vZaS6b6RpxZ0qwF+ysAdJbd87MOwgAAAGPCnpQmwAABAMARjBEAiBR VSozS/iLOhWeGgm7FwG88CPhPCYUbgMTmuffEuromgIgA8i07cuGvCWXa67kXCRe 5aQl7n2QUL5oy7YHMfVHtl8AdQATSt8atZhCCXgMb+9MepGkFrcjSc5YV2rfrtqn wqvgIgAAAY8KelHVAAAEAwBGMEQCIBCwY4b5BXRAbQ/dZQdOycPxV1IqTTXYH/8N 8r8A4h5zAiAbKG8Jw3KuqNeBNlX31rA3+Epaem0oaGKCNSZ68KXH6zANBgkqhkiG 9w0BAQsFAAOCAQEAVqHhDg56pnBPHuwV/5nDZja7MITuhh7TUF719iO0ZuDWbkva 8YpbEi9NFhEezf4zc97CwZMDdcwN2mUzRkV3Djhqf46+PXj6dT+ZUlEgMEmTm0n5 aGo0EhGFmCpe3yh9Z9Cg2QV/6z4X3D9TE9BFoULIi1GYzV+mFUs9Na7M0wHTCuKQ Ap9/rLiOtLNQbIyW1xswdkxpik32YA0xFrEI0OL77GiLUhVd3r+/V3E4Bu7GvFc7 WrY035GO5kzcyu8FzBGk57SzVUFF7TeWXYxCRJKPUkARaTztrRZe3o3jdyTQ8e8k aa6masR4LAr6BegDz6JvbZr/NHBcLI8ip8icxg==

MIIG1jCCBL6gAwIBAgIQNMarBE42mRJRyCULbJTWwDANBgkqhkiG9w0BAQsFADA7 MQswCQYDVQQGEwJFUzERMA8GA1UECgwIRk5NVC1SQ00xGTAXBgNVBAsMEEFDIFJB SVogRk5NVC1SQ00wHhcNMTMwNjI0MTA1MjU5WhcNMjgwNjI0MTA1MjU5WjBHMQsw CQYDVQQGEwJFUzERMA8GA1UECgwIRk5NVC1SQ00xJTAjBgNVBAsMHEFDIENvbXBv bmVudGVzIEluZm9ybcOhdGljb3MwggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEK AoIBAQCXVx8rdbF7/xY44CaSqzzGo5BhvzA8knxC/3KJYVzTf+CkOvMxMUDub8b0 h38MDujm/RKZhBNOWbKhxF3U61ZVhcR9xOCciuS/soT80m3BByxAKcZsNka0jCA4 XRkglDaAFxCHEZ06MOnvXsSOZDfPYahbQ3VFCVycJuhlHdAwSpmceQwcRYkR6YgX wTiyzCNGivMKAmRS3dItqDOmDW/nxiDFq/Jd8VWY7GFkwbbAeqYId8FjN8zfvafu nsB9SLFkUjPPMeqfmC7Bdh7HMxLpaOXROwH201cmlebiPkn0xSFxXFqwhhr6yN8U QYZ3O/+xdHLrS6DS9+CJUF6d09ijAgMBAAGjggLIMIICxDASBgNVHRMBAf8ECDAG AQH/AgEAMA4GA1UdDwEB/wQEAwIBBjAdBgNVHQ4EFgQUGfhYLxTWpsybBJgIDUzX qwCng2UwgZgGCCsGAQUFBwEBBIGLMIGIMEkGCCsGAQUFBzABhj1odHRwOi8vb2Nz cGZubXRyY21jYS5jZXJ0LmZubXQuZXMvb2NzcGZubXRyY21jYS9PY3NwUmVzcG9u ZGVyMDsGCCsGAQUFBzAChi9odHRwOi8vd3d3LmNlcnQuZm5tdC5lcy9jZXJ0cy9B Q1JBSVpGTk1UUkNNLmNydDAfBgNVHSMEGDAWgBT3fcX9xOiaG3dkp/UdoMy/h2Ca bTCB6wYDVR0gBIHjMIHgMIHdBgRVHSAAMIHUMCkGCCsGAQUFBwIBFh1odHRwOi8v d3d3LmNlcnQuZm5tdC5lcy9kcGNzLzCBpgYIKwYBBQUHAgIwgZkMgZZTdWpldG8g YSBsYXMgY29uZGljaW9uZXMgZGUgdXNvIGV4cHVlc3RhcyBlbiBsYSBEZWNsYXJh Y2nDs24gZGUgUHLDoWN0aWNhcyBkZSBDZXJ0aWZpY2FjacOzbiBkZSBsYSBGTk1U LVJDTSAoIEMvIEpvcmdlIEp1YW4sIDEwNi0yODAwOS1NYWRyaWQtRXNwYcOxYSkw gdQGA1UdHwSBzDCByTCBxqCBw6CBwIaBkGxkYXA6Ly9sZGFwZm5tdC5jZXJ0LmZu bXQuZXMvQ049Q1JMLE9VPUFDJTIwUkFJWiUyMEZOTVQtUkNNLE89Rk5NVC1SQ00s Qz1FUz9hdXRob3JpdHlSZXZvY2F0aW9uTGlzdDtiaW5hcnk/YmFzZT9vYmplY3Rj bGFzcz1jUkxEaXN0cmlidXRpb25Qb2ludIYraHR0cDovL3d3dy5jZXJ0LmZubXQu ZXMvY3Jscy9BUkxGTk1UUkNNLmNybDANBgkqhkiG9w0BAQsFAAOCAgEAo2bsQ2xL Dcyodieqjd+uy/lfxDw/MbrAq/ZaNFkIlcypUYamOM4vrm5rz8oLjPCoLkJ48P+n P08Gkcl5Q6q6VFcZLia+U3gfHXrkyqToQlrtViGCGH3xA4u56XtMHGXSdk9vQ0yD nW5f7bUEkp+uvcKewrOvNcpbIAgD4eU7gdOS0w7BagcFRBgTKBw2s3z73fRZtouJ g/atmWYtXbBsfNjph+pCh+h5sbSyZUVzO5AemyjpYYYNMWDQrTXq+7O8zIPuPaNE SjEexuzn+VjHG90RlUK1LygARi+Ir0opD2w6erb/hK8Eea7MFdKQ2ASqNBGJggNo 5vfPVvjHiL+Antmh7mQSKL+4YwFU64d4KK9k0C1mbJethDQFKcjTK1vMvnXFiups IuyTqwKauo7u2zMKzY4r3VYOW9TpMyLPFIY8pII5GyNzXlL0F4nscOvduTEPEYqx eNJfpDDPY/DO8WfxgdRTy2W3D/UoAulb+Y+nuzGGCtFQrsSMQX487R+aY0nWot/h ajef6BcPuxhDfQrg5IafrISVmcJAplb3tXhh0sz7RbYz6jf1bke4eU5fnrTMtGlV teUL2vjrfUPHW07kBJuaQ7sxORNV3bpHisOnHj+AriQzCn5vINpSHW6hTm7IfRkb ltu/aQrsMuUhP7HE/v+uXe5CuboV5ubZhHU=

I am getting a message that secure connection failed, it is happening for Amazon.com and maybe netflix as I can't log on or access the sites

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?

please provide directions for fixing the navigating inside NEwsmax site

Secure Connection Failed

The connection to www.newsmax.com was interrupted while the page was loading.

   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.

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 encountered a problem: when trying to open the Prohoster.info website on my computer, a notification appears that the connection is not secure. I don’t understand how to fix this error and what needs to be done to gain access to the hosting?

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.

Since your last update, I can't access amazon anymore without a security warning. I know that my connection is private and secure. The only thing that's actually happening, is that my Browser is interfering with me without cause. Can you please make that stop ?

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.

I am unable to access my usual sites such as @creates or Civil service.Gov.UK or Civil Service Jobs - GOV.UK I am getting this message when I attempt to:

Firefox detected a potential security threat and did not continue to atcreates.com. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details.

"civilservicejobs.service.gov.uk 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 web site, and there is nothing you can do to resolve it."

Advance provides: Someone could be trying to impersonate the site and you should not continue.

Web sites prove their identity via certificates. Firefox does not trust civilservicejobs.service.gov.uk because its certificate issuer is unknown, the certificate is self-signed, or the server is not sending the correct intermediate certificates.

Error code: SEC_ERROR_UNKNOWN_ISSUER

View Certificate

These are ligit websites that I need for work. Heeeelp!