I-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?

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 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.

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!

I am getting the below message when trying to log into the EFTPS site. I have never had this issue before.

Did Not Connect: Potential Security Issue

Firefox detected a potential security threat and did not continue to www.eftps.gov because this website requires a secure connection.

What can you do about it?

www.eftps.gov 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.

Learn more…

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'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.

At your recommendation I signed up to Ad Avoid and now FireFox tells me that I could/should not access BT.Com because of the certificate issued by Ad Avoid

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?

Hi, Since three or four months, whenever I log into Outlook live, either on Mac or Windows PC, I get a security warning saying that the information will not be secure (Please see attachment.) When I log into the same account, from Edge for example, I do not get the warning popup. I really enjoy using Firefox and would love to continue but this case is worrying me a bit. Any idea to help? Thank you very much, Mathieu B.

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 confirmed with my host provider that my website is in a secure environment, but when I access three form pages that end in "php" there is a broken padlock icon in the address bar and says that the connection is not secure.

I checked other browsers (Edge, Chrome, & Brave) and all show a secure connection. So this only happens in the Firefox browser (v141.0). I'm using Windows 10 64bit.

Has anyone else had this issue? Any suggestions on how to fix?

The form is how my clients order on my website (no financial info is entered on the form, just data), and I fear that if they are using Firefox and see it's "not secure" they will leave.

I read the The Times in the UK and have no problem viewing on my iPad and Google Pixel phone using the Firefox browser. However on my laptop using Firefox I get a screen that says Secure connection failed and recommends contacting the vendor as there is no workaround. On microsoft Edge there is no problem I like Firefox but for me this is a major limitation. Any ideas or suggestions welcome

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 !!!!!!!!

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.

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 anti-virus reports that 30 to 100 times per day, it blocks firefox.exe attempts to establish a connection relying on an expired certificate to to www.temu.com. Can you please stop your attempts ? Or tell me how to stop them ?