Firefox Community Forum

I am trying to access certain HTTPS websites and some of them show PR_CONNECT_RESET_ERROR in Firefox. This error is not present in Edge or Chromium.

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.

The only fix that works is to use Troubleshoot Mode every time I visit these websites which is not practical. Any ideas on what could be the problem?

I don't know if this is relevant but one of the websites that does not work is https://alexan.com.ph/

In Firefox, and only in Firefox, I get 'Failed to verify your identity' on these sites. I have updated MacOS and Firefox, rebooted, tried a different DNS, and disabled all of my extensions. With extensions disabled I don't get the error, but the login site won't accept my login at all. See the attached image. I can't think of anything else to try.

With Firefox 135.0 i cant reach google.com but google.se i can.

I make daily images of C: and today i managed to go back one day to 2025-02-06 but accidentally chooses 2025-01-06 and with the older version of firefox i could reach google.com

I have tried to delete cookies. DNS over HTTPS off. No proxy in connection. Add-ons off but to no avail.

The font size in "Manage Bookmarks" is way too large, both in the sections list menu on the left and the list of bookmarks. I checked my userChrome.css file as well as the layout.css.devPixelsPerPx entry in about:config and there's nothing there to explain why only the "Manage Bookmarks" text is so large.

It's possible I changed a setting somewhere that's causing this. But I'm stumped re: what setting might be controlling the font size in only that UI. All other Firefox text sizes are good.

Thanks to anyone who knows where I should be looking

Firefox 134.0.1 (64-bit) Windows 10

[redacted] problem you [redacted] im having issues with the video and ads as all of my apps are disabeld nothing works and firefox it self causing probs and no one is helping out.

Current Behavior When Firefox is set to offline mode (File → Work Offline), the Developer Tools Network tab does not display request body of requests that web applications attempt to make. This creates a significant gap in debugging capabilities, as developers cannot inspect request payloads details that would normally be visible.

Requested Enhancement Enable the Network tab to capture and display attempted network requests payload even when offline mode is enabled

When saving images from websites using the save image as feature, Firefox will freeze up and not register any mouse click or anything instead making a ding noise every time is register a mouse click. This will continue for like 30 seconds before it becomes normal then it will repeat this for every image. How can I solve this?

Hmm. We’re having trouble finding that site.

We can’t connect to the server at data.digital.costco.com.

I am using 140 ESR version on linux with Cloudflare's DNS over HTTPS and with DOH active for some reason resolving a domain like d3oklwo3y1bx83.cloudfront.net will resolve to local host IP 127.0.0.1.

I am using firefox about:networking#dnslookuptool to test resolution of the domain d3oklwo3y1bx83.cloudfront.net Both with DOH on and off the resolution remains local host. I tried another browser on the same workstation and I was able to receive a resolution of 13.225.193.203 13.225.193.133 13.225.193.64 13.225.193.58 Why is firefox ESR not able to resolve that domain? What are causes ?

Is is firefox dnslookuptool results.

Hmm. We’re having trouble finding that site.

We can’t connect to the server at data.digital.costco.com.

Hmm. We’re having trouble finding that site.

We can’t connect to the server at data.digital.costco.com.

NOTE: I have marked this as "Solved" because I figured out the problem described below, and I fixed it. See my following message here for a description of my solution.

Original message starts here ...

I'm using Firefox 144.0 under Debian Linux. I've used Firefox on this machine for years with no problem. Firefox can easily connect to literally thousands of web servers on the internet, both via HTTP and HTTPS.

But now, I'm having an issue:

I started running a web server on the same machine that Firefox is running on. This server only listens for non-HTTPS connections on port 80. I am not using any proxy server with Firefox.

I can easily and directly connect to my local web server's pages from my local machine from Chrome, w3m, curl, and direct telnet connections to port 80 ... all of which are addressing the publicly accessible domain name for my local web server. However, However, Firefox refuses to connect to any URL's on my local machine, and it gives me the following explanation:

Unable to connect

Firefox can’t establish a connection to the server at [ my server's domain name ].

   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.

In Firefox, I have all auto-forcing of HTTPS disabled by means of Don’t enable HTTPS-Only Mode turned on.

I get the same error in Firefox whether I connect via a URL like "http://MYFULLDOMAINNAME" or a URL like "http://AAA.BBB.CCC.DDD", where "AAA.BBB.CCC.DDD" is my machine's publicly accessible static IP address and "MYFULLDOMAINNAME" is the long-standing, publicly accessible domain name for my machine ... both with and without a suffix of ":80" on the supplied URL.

And again, all other browsers on my machine have no problem whatsoever connecting to my own local web server on this same local machine of mine using those same URL's.

And all browsers (Firefox and otherwise) that are running on other machines all over the internet have no problem connecting to that same web server via the same URL's that I described above

Also, I have no firewall rules on my machine which would block access to my own machine's port 80.

What could be causing this error in Firefox, and what might I be able to do to fix it?

Thank you very much in advance.

UPDATE: Just a bit more information. Looking at the web logs, I see that Firefox's request never even reaches my local web server. In other words, Firefox itself is not even trying to make a TCPIP port 80 connection to my local web server in the first place

Unable to connect

Firefox can’t establish a connection to the server at mesp.finance.gov.bd.

   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.

Within a minute of starting Firefox up, it loses internet connection and prevents the computer from connecting to anything else. Using Ethernet or Wifi doesn't work. The only thing that corrects it is restarting the computer. List of things we have tried: Troubleshooting Mode in Firefox Removing all addons Uninstalling and Reinstalling Firefox with the latest update Disabling DNS over HTTPS Clearing Firefox's DNS cache Clearing the computer's DNS cache Adding IPv6 to our standard IPv4 connection Rebooting the router Used a new Firefox profile Run a virus scan

This is on Windows 11. There are multiple other computers on the network, with W10 and W11, and none of them are having this issue. I've tried everything I can think of. After losing connection, it still pings 8.8.8.8.. Is there anything else we can try?

This has been a problem for me for a very long time, and I'm tired of having to use Chrome every time there's an update to Firefox.

The issue I have is that I will get the notification saying there's an update. I click the button to update now, the browser opens the auto download page and I get a not secure connection warning. The only work around I've found is to use Chrome, and sometimes I can use the "Other downloads" option.

I'm not running a VPN, or any other networking software on my pc. This is for the full program, not the Windows Store app.

Secure Connection Failed

An error occurred during a connection to download.mozilla.org. The server uses key pinning (HPKP) but no trusted certificate chain could be constructed that matches the pinset. Key pinning violations cannot be overridden.

Error code: MOZILLA_PKIX_ERROR_KEY_PINNING_FAILURE

   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.

the msg returned

Hmm. We’re having trouble finding that site.

We can’t connect to the server at marvelsearch.com.

If you entered the right address, you can:

   Try again later
   Check your network connection
   Check that Firefox Developer Edition has permission to access the web (you might be connected but behind a firewall)

i am using a local dnsserver and firefox is connected to it. is this the reason? if so how can i disable this? other firefox features are working beautifully.