Firefox 社群討論區

Why are you closing the baked-in cert expiration support thread two days before it happens? Wouldn't it make a whole ton more sense to leave it open during the actual problem period?

https://support.mozilla.org/en-US/questions/1468274

I have started receiving a secure connection failed error message for a portal log-in website that worked fine for the past 6-7 months (see attached document). Other people in my group use Firefox and Bitdefender to access the portal and none of them are having this issue.

I originally believed the problem to be my anti-virus (Bitdefender) and worked with them to resolve the problems. After trying various solutions including clearing my cache, using private mode and turning off different components of their software, Bitdefender believes the problem is with my browser setting and not their software. I also tried accessing the portal using Chrome in both regular and incognito modes and cannot access the site which would seem to rule out the problem being a Firefox browser problem but contacting Firefox support seems to be the next logical step.

I have been to the Firefox FAQ and saw similar problems with potential solutions - DNS over HTTPS, TLSKEYLOGGING issues, add-on exceptions - none of which worked. I have the most recent version of Firefox and am running Windows 11 home version.

Sometimes if I hit refresh after receiving the error message, the browser will try to connect and I will get a server time out message. If I keep hitting "try again", sometimes the portal log-in screen will appear and allow me to log-in. The key word is "sometimes" since often I just keep getting the server time out message.

Any ideas for me to try from this forum?

I have an website which I prior to this error message have visited many times on Firefox and had no problems. Recently though around two days ago I noticed that I couldn't get in and was met with the following message "Warning: Potential Security Risk Ahead". I can't bypass it apparently and I really need to be able to access this site as it's a University site.

I can access the site on other browsers such as Chrome and Edge but I use Firefox as my default browser and I'd like to keep it that way. I'd appreciate any help I can get.

Said link: https://canvas.gu.se/

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.

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

Hello,

Since this morning, I haven't been able to access Bsky on my laptop because of a supposed HSTS risk, which means I can't add an exception to visit it. I use Firefox on my Android and going to the mobile version of the website lets me in no problem, so I assume there's an issue with my laptop.

I'd usually wait a few days and let it solve itself but just in case it's something on my end, I'd like to solve it! I'm on 151.0.4 (64-bit), don't use a VPN or an anti-virus, I have a couple of privacy add-ons but they've been here forever and they've never caused a fuss. I can post a screenshot of the error code and the certificate it sends me if it's any help.

I'd appreciate any pointers! Thanks!

Untill last night i could conect with that site https://imtw.ru and its sub forums without eny problem . Today when i press the link i recieve a message that the connection is rejected "Failure to secure connection". As you van see it has the https:// infront and i repeat i was able to connect last night. What may be wrong?

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.

When trying to access many popular websites with Firefox on my Fedora 43 installation, I am greeted with a security warning page with the SEC_ERROR_UNKNOWN_ISSUER error. For most of these websites I can simply accept and continue, but HSTS-only sites will not permit this.

Affected websites include but are not limited to (based on exceptions in the certificates section of Firefox settings):

• github.io (many subdomains)
• purdue.edu (many subdomains)
• iu.edu
• ebay.com
• cbsnews.com
• iwm.org.uk
• home.cern
• celestrak.org

Any help in resolving this is appreciated.

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

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.

When I bring up the certificate-expired URL

<https://oaklandwiki.org/>

in Firefox 149.0 on Windows 11 I am told "You have added a security exception for this site." But not how to remove it. How do I do that? I did not see anything in Settings or about:config; did I miss it?

Hi, I try to use Firefox for my job and faced with the problem that I can't open state owned website due to sertificate signature error. I ready to take a risk but I can't find the button "Proceed.. (Risky)". This button simply not showing. In th same time in mobile version I saw this button, could take permssions myself and open the website. I tryed to add root and sub sertificates of the Goverment, tryed to add the site address to exclusions -- all these steps don't work. I can't open the site and can't find button "Proceed.. (Risky)". Moreover, in the same time, I can open this website without any questions and problems with Safari and Chrome.

I use the last Firefox version (153.0) from Firefox official website.

How can I resolve this problem in Firefox? Please help me

I have a home server 192.168.0.240 in my local network. Firefox does not let me in to my own pages. On the address line appears text "Not secure",

I have found no way to get in. I have there REALLY IMPORTANT TOOLS AND MATERIAL and I need it AS SOON AS POSSIBLE !!!!

This is really stupid. I have used these pages until this weekend. I have had this problem many years, but always found some way to make it work. I am NOT going to buy a certificate to every server I have home. it costs $$$$.

I'm getting a PR_CONNECT_RESET_ERROR on my PC when trying to web browse. Same problem with other browsers. Was working fine till a few days ago The URL box has 'Not Secure' before each URL address I try. Have looked up solutions on YT to no avail eg clearing cache etc

My Laptop has no problem with this.

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.

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 - - -