Firefox Community Forum

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.

Server Not Found

Firefox can’t connect to the server at student.maharashtra.gov.in What can you do about it?

Try connecting on a different device. Check your modem or router. Disconnect and reconnect to Wi-Fi.

Learn more…

I keep getting this message at the top of each site I go to: "You must log in to this network before you can access the Internet" It thinks I'm on a captive portal?? I'm at home on my own internet network. Why am I getting this message?

Bonjour, depuis la mise à jour je ne peux plus me connecter sur mon NAS.

Il semble y avoir un problème sur ce site

Firefox ne peut pas se connecter au serveur à l’adresse .....

Par contre je peux me connecter depuis Safari donc le problème semble venir de Firefox.

how do i delete or remove the message about could connect error

Contributor note: See also /questions/1576275 for the detailed error message.

when i open microzain website he give me these error

Server Not Found

Firefox can’t connect to the server at microzaib.com What can you do about it?

Try connecting on a different device. Check your modem or router. Disconnect and reconnect to Wi-Fi.

I can't access FSIS website which I need to do so for my job. This is what I get

"Firefox can't connect to the server at usda.gov Try connecting with a different device Check your modem or router Disconnect and reconnect to Wi-Fi"

I can't do any of those things because they make absolutely no sense. Nothing is wrong with my router, Wi-Fi. It's your program.

For over a year, my browser occasionally loses connectivity. It may work for 3 hours or 3 days, but inevitably new tabs will stop working and then slowly the others will stop as well. When this happens, none of my other browsers are impacted. They work fine. It is only Firefox. The only solution is to close everything and lose all my work.

Once I do that and restart Firefox, I receive an error message telling me I am using an older version of Firefox that is not compatible with my profile. The only solution that brings me back to the best starting place is to re-install Firefox.

My company IT spent 3 days trying to find the problem and couldn't. I have uninstalled and reinstalled so many times. All extensions are turned off, as are the two add-ons. I have been using Firefox for over a decade and prefer it to all other browsers, but I need to find a solution or I am going to have to move on. Help!!!

when i enter a web address to enter a search address to find the finformation being sent to me thaty is located at this address; kdrive.informiak.combold textI get the message  ;

Hmm. We’re having trouble finding that site.

We can’t connect to the server at kdrive.informiak.com.

If you entered the right address, you can:

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

I just started up my new MacBook Pro, M5 pro machine and Firefox will not work. Tahoe 26.3 is OS.

Dale Howard Jonesboro, GA

PS--Safari and DuckDuck Go browsers are working normally.

I need help with a problem that has tortured me for weeks. I use debian 13 with plasmakde. I don't know why, but when I connect to a wifi after some time it doesn't work anymore ONLY with Firefox. I can perfectly use any other app which requires internet but firefox. Sometimes it gives me the error "The connection has timed out", sometimes the error "Unable to find the proxy server" (even if I selected no proxy in the network settings). I searched online but I couldn't find anything helpful, so I can only hope to find a solution in here. Thank you very much in advance!

While browsing on my desktop , I am unable to open E Shram Card blog. it appears like there is an error in connection , but despite of good connection, cannot open it.

Hello everyone,

We are currently investigating an issue where browsers are sending HTTP requests with Connection: close in the header during integrated Windows authentication (NTLM authentication) via SAML Service Provider (SP), leading to premature termination of the TCP connection.

This behavior occurs in the middle of the authentication process, preventing the NTLM authentication from completing and subsequently prompting for re-authentication.

We have observed the following browser behaviors:

Chrome and Edge: These browsers function without issues, communicating with Connection: keep-alive. Safari (macOS): Older versions of macOS with Safari exhibit the Connection: close behavior, leading to authentication failure. Newer versions of macOS with Safari work correctly with Connection: keep-alive. Firefox (macOS): Even on the latest versions of macOS, Firefox continues to attach Connection: close, resulting in authentication failure. Upon reviewing logs, we've identified that various browsers attach the Connection: close header during the NTLMSSP_NEGOTIATE request in the NTLM authentication sequence. Although this happens in an environment with a load balancer, we have confirmed that the load balancer is not modifying the header; rather, the client (browser) is adding it.

We would appreciate your insights into the conditions under which Firefox attaches Connection: close to HTTP requests, especially considering the differences across macOS versions and other browsers, addressing the following points:

Are there any known conditions or past cases where Firefox outputs Connection: close in an NTLM authentication environment via SAML SP? Given that older Safari versions show similar behavior, we are also considering if there's a common factor depending on NTLM authentication and browser version. What are the general heuristics, logic, or triggers for a browser to decide to "close" a connection or to attach Connection: close? We are particularly interested in cases that occur mid-authentication process. Could specific configurations (e.g., the combination of SAML and NTLM authentication, or the presence of an intermediate proxy/load balancer) potentially influence Firefox's Connection: close behavior? Are there any additional logs or debugging information we should collect from the Firefox client side to further pinpoint this issue? Any guidance or suggestions you could provide to help us resolve this problem would be greatly appreciated.

Thank you.