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To be honest. Firefox is starting to be a big pain to use. I'm starting to see more and more of this screen where it say's "Be careful. Something doesn't look right" Even when i go to the advance and say proceed. Nothing happens and i'm getting no where. I know many of the sites don't have anything to do with asking for credit card, Scam or even having popup's. I test the sites in other browsers and there work without any issues. But Firefox is starting to lock me out of many sites due to this. How can i make this stop. As i used Firefox for many years.

The sample that is in the screenshot is a Anime data base that i have also used for years. But today shows this. But was working fine yesteday. What is going on and how can i fix it. So i can start using the browser that i love on the sites i want to.

I am writing to report a recurring technical issue that began appearing today across multiple devices.

When attempting to access Google websites (specifically Gmail and Google News) using the Firefox browser, users are being prompted to identify themselves via a security certificate. Previously, this authentication step did not occur, and access was seamless.

Key Observations:

Impact: We have confirmed this behavior on three firm-issued computers as well as one personal device.

Browser: The issue is isolated to Firefox; other browsers appear unaffected.

Timing: This behavior was not present yesterday; it started manifesting today.

We suspect this may be related to a recent network configuration change, a new security policy rollout, or a browser update that has altered how Firefox handles trusted connections to Google services.

Could you please inform me whether there have been any recent changes to our SSL inspection proxies, root certificate stores, or DNS configurations? Additionally, does anyone else on the team have visibility into a widespread incident affecting Google certificates, or should we proceed with troubleshooting individual profiles?

Ever since the update to iOS 26.4, I’m unable to access insecure or untrusted sites. I first noticed this when trying to get to some devices on my local network, but I tested an insecure site on the internet and it happened there too. What’s weird is that Safari does still let me access these sites after proceeding through the warning as expected (albeit with a refresh which is new, maybe a bug), but Firefox will just load for a split second and stop.

Just a quick rundown of some additional info:

- Firefox has been updated to the latest version, 149.0. - The local sites are ones I’ve previously given trust to - Firefox has local network access enabled in settings - This also occurs on iPadOS 26.4 - I did some more testing while writing this and it seems intermittent? For example, I have a server with several docker containers, and I can access some of them if I put the port in with the IP but others I can’t. I also have a device that I can get to via hostname but not IP. - I also downloaded Chrome to test things there and I get the “this connection isn’t private” message with the option to proceed anyway, and I’m able to access these sites there.

I’m not sure if this is something on Firefox’s end, Apple’s end, or a combination of the two. Either way, I wanted to see if there was anyone else experiencing this issue or if it’s just me.

Hi Love Firefox and use it every day to manage clients Google Ads accounts. Updated to latest version and now I'm getting this warning when I'm trying to access ads.google.com Doesn't appear that I can add an exception, is there a work around that I can use. Look forward to hearing back. Thanks in advance

Paul

An error occurred during a connection to in.pinterest.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 web site owners to inform them of this problem.

Loading website for BacaPoa.frontsteps.com does not work, now fails ("not secured") . This is business site I have for years.? [windows 11] Is the a bypass or override I can do? JR

Have used Firefox for years. Today, went to standard sites (eg weather info, local blog site) and get told they aren't secure and can't be loaded. Have tried re-installing Firefox, clearing cookies but no change. No problem with same sites from Chrome. Message is:

Looks like there’s a problem with this site

www.portlandbirdobs.com sent back an empty page. What can you do about it?

   The site could be temporarily unavailable or too busy. Try again in a few moments.
   If you are unable to load any pages, check your computer’s network connection.
   If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the web.

Error Code: NS_ERROR_NET_EMPTY_RESPONS

I was going to look at a friend's website that has an SSL-certificate, has had it for years, which has been working all that time. Now Firefox informs me: "Firefox doesn’t trust this site because its certificate isn’t valid for www.wuwei-school.nl. The certificate is only valid for: wuwei-school.nl."

Really? I pretty sure there's nothing wrong with the certificate and I was taught that the "www" component is not important as a prefix for the domain name in a URL. It is just a shorthand code to show that the address is a URL. Can Mozilla fix this issue? Or, at least, explain?

Thanks

Firefox's full message: - - - Be careful. Something doesn’t look right.

Firefox spotted a potentially serious security issue with www.wuwei-school.nl. 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?

The site is set up to allow only secure connections, but there’s a problem with the site’s certificate. It’s possible that a bad actor is trying to impersonate the site. 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 its certificate isn’t valid for www.wuwei-school.nl. The certificate is only valid for: wuwei-school.nl. What can you do about it?

Probably nothing, since it’s likely there’s a problem with the site itself. Sites use certificates issued by a certificate authority to prove they’re really who they say they are. But if you’re on a corporate network, your support team may have more info. If you’re using antivirus software, try searching for potential conflicts or known issues.

View the site’s certificate

Learn more about secure connection failures

Error Code: SSL_ERROR_BAD_CERT_DOMAIN

Aug 21, 2026 11:10:31 PM GMT+2 - - -

Firefox is giving me an error on https://stemgateway.nasa.gov but the site is perfectly accessible using MS Edge and using Firefox on another computer. I uninstalled and reinstalled Firefox, changed the proxy settings to not use a proxy, tested a VPN, and changed DNS servers. Below is a picture of the error and of the certificate which seems to be present in Firefox already.

I've never had Secure Connection Failed warnings before, but now I am getting them often. I don't want to stop using Firefox, but it seems I can get to these sites via other browsers.

Secure Connection Failed

An error occurred during a connection to citizen.jhpolice.gov.in. 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.

Learn more…

Secure Connection Failed

The connection to www.tab.com.au 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.

Clear Error code: PR_END_OF_FILE_ERROR This is only on Amazon.com. Secure Connection Failed

An error occurred during a connection to www.amazon.com. PR_END_OF_FILE_ERROR

Error code: PR_END_OF_FILE_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.

Learn more…

Доброго времени суток.

Я установил сертификаты по инструкции, которая лежит на s.sber.ru/70VQ2B . После этого не прогружается полностью окно входа на online.sberbank.ru (не видно содержимого фреймов). Проблема полностью аналогична описанной здесь: https://support.mozilla.org/ru/questions/1597415

Firefox ESR115.40 (64-разрядный, Windows 7) - страница выглядит, как на скриншоте по ссылке выше.

Установлены скачанные сертификаты в самом браузере, они отображаются в разделе Управление сертификатами -> Центры сертификации. После этого абсолютно ничего не изменилось.

Может, надо еще что-то сделать? Или на Firefox ESR115.40 вообще работать не будет? До перехода на сертификат от Минцифры России проблем не было.

Zachowaj ostrożność. Coś tu nie gra.

Firefox wykrył potencjalnie poważny problem bezpieczeństwa na witrynie ohttp-gateway-merino.services.mozilla.com. Ktoś podszywający się pod nią może próbować ukraść dane karty płatniczej, hasła, adresy e-mail lub coś innego.

Witryna „ohttp-gateway-merino.services.mozilla.com” określa poprzez HSTS (HTTP Strict Transport Security), że Firefox ma się z nią łączyć jedynie w sposób zabezpieczony. Dodanie wyjątku w celu odwiedzenia tej witryny jest niemożliwe.

Hello,

The website I log in for internet banking (https://www.sparkasse-rhein-maas.de/de/home.html) is shown as written in brackets when opened in Edge, but as www.sparkasse-rhein-maas.de/de/home.html when I open it in firefor. And Firefox tells me it's not safe when I want to log in. BUT - as I've only just discovered when I copied and pasted it in here - when copied it shows as https://www.sparkasse-rhein-maas.de/de/home.html, so safe after all? How can that be? I hope there's a good explanation.

Thanks in advance Bettina

Moderator note: This question has been edited to correct the formatting.

Subject: Urgent Assistance Needed with Certificate Installation

Dear Team,

I hope this message finds you well. I am in urgent need of assistance regarding a Linux-based system where we have the Firefox browser installed. I need to establish a secure connection with one of my servers, which requires the installation of a certificate.

However, I am unable to locate the certificate export button in the certificate view or anywhere else in the browser. I have tried several methods without success.

Could you please help me with this issue as soon as possible? Your guidance would be greatly appreciated.

Thank you very much!

Best regards, Kishor