Every time I start Firefox lately, it keeps prompting me: "You must log in to this network before you can access the Internet." I have no idea what this means and have no problem accessing the Internet in any case. What suddenly started causing this !#@%$ message and how do I turn it off?

The server not found response started right after two changes: 1) Firefox last update 2) opening an account with Mozilla. It usually works on second request but occasionally not. Thanks for your help in advance.

when i work in any web page and i try to back to previous page browser disconnect the page and shows loading page error (problem loading page). Is this a browser problem or any network issue , after update this shows multiple times when i try to go to previous page . 'problem that i face ' Server Not Found

Firefox can’t connect to the server at scholarship.up.nic.in. What can you do about it?

   Check to make sure you’ve typed the website address correctly and try again in a few moments.
   Check your network connection.
   Check that Firefox has permission to access the web (you might be connected but behind a firewall).

Learn more… Try Again

Setup: macOS Tahoe (26.4) and Firefox 149.0

=

Behavior: Out of the blue this morning, every website I try to visit in Firefox returns "Looks like there’s a problem with this site". Every other browser works fine.

Things I've tried, that haven't fixed it: - Ruled Out DNS: Sites like 1.1.1.1 and my home router's IP return the same issue in Firefox, but also resolve in any other browser. - Firefox Safe Mode: no fix - Deleted All Settings, Reinstalled Fresh: - Removed the Firefox App, deleted:

       - ~/Library/Application\ Support/Firefox
       - ~/Library/Caches/Mozilla
       - ~/Library/Caches/Firefox

...and then downloaded and installed 149.0 fresh. - Refreshed Firefox (via [link] - about:preferences (toggled between FALSE and TRUE, testing each time) via this YouTube video

- network.dns.disableIPv6

- network.dns.disablePrefetch
- network.dns.disablePrefetchFromHTTPS
- network.dns.disable

....and in desperation, I checked my Mac for Malware (clean)

I'm at a complete loss: every other browser works, but Firefox is a 100% fail for all websites. Any thoughts?

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?

Issues with redirect. A group I am a member of uses Constant Contact. An email is sent with a link to a report. Receive this error:

Server Not Found

Firefox can’t connect to the server at deuaxb4ab.cc.rs6.net. What can you do about it?

This worked last week.

Firefox 152.0.4. Win10

Firefox won't load any webpages. Every website I try to open fails to load, even though my internet connection is working. I have restarted Firefox and my laptop, but the problem till exists. I am using a Lenovo laptop. Please help me fix this issue

I'm on a private home network with an internet connection. When I try to use Firefox it displays a message saying "You must log in to this network before you can access the internet".

Many websites, e.g. Amazon, won't load and an 'Open network login page' button is shown. When I click this it takes me to a Mozilla page talking about Captive Portal, but there's nothing about how to stop this happening and access those websites.

Other browsers, e.g. MS Edge, or Brave, have no problem access these websites.

How do I fix this problem?

As of Aug 23rd, Firefox no longer connects to the internet (not site-specific) with this message: Unable to Connect. All other browsers work with fast loads. FF has been incredibly slow loading pages for weeks now but it would eventually connect until today. It is not a network/firewall issue as I've checked to make sure all was set correctly. I have cleared cache, turned VPN off, refreshed app, uninstalled/reinstalled and nothing has changed.

If I find the same tomorrow, I will just have to stop using altogether and choose another default browser as there is no point in a browser that is slow and unreliable. It's a shame since I've been using FF for many, many years.

I routinely am not able to open registration to conferences or other links to long web addresses. This screen message from Firefox appears:

"Server Not Found

Firefox can’t connect to the server at gi9zc6sab.cc.rs6.net. What can you do about it?

   Check to make sure you’ve typed the website address correctly and try again in a few moments.
   Check your network connection.
   Check that Firefox has permission to access the web (you might be connected but behind a firewall).

That message appeared for this https://gi9zc6sab.cc.rs6.net/tn.jsp?f=001T5esaGIPGizJmjnFH_ZN0rs2nRmFvfg68IUb5lZCQmIAPWdC8rFl0Y1xbniCS0F-q4zVJMAgN3whbcuThS0wDfZevAHUBUCIbKas_wNb6IUJRAHRhiCDsq5_kmYDK-Gwv2w6vv76FnR39uAtOCKdr_ttlxoNJN7WIwMD4ZlQBENHQ920CL4dvvDmhESGhC9TSU-FvwD5zS2y1m0fjSgUiuFw0HzjsTjKMljdebV-fUXu5pxZFF4nQqJ156RWpzEzobANY217MXdmMlwqBqX_1EoztmWAB2LfNJz-Z-9ZVVejG_saHWKFvdbZ2BrQlX4Y1fpYrTz5Xzx8AvB4ybvXJA==&c=yp6c6A5fB7yDTLMvkly_lvoPm2JVn0awZB8o-xRVaJpx_MPafsrX3A==&ch=c_dP5vdY4uwNFMGk8OzrTttJtbNgGv0RSdMckxp2d-NbUWrheIutEQ==

That long link was embedded in this conference announcement:

Join the Connecticut Institute for Resilience and Climate Adaptation

for our annual summit at the

UConn School of Law, Hartford, CT

Friday, November 20, 2026

9:15 am – 2:30 pm

Agenda

8:45-9:15: Registration and Coffee

9:15–9:25: Welcome Remarks

9:25–9:50: CIRCA Update Presentation

9:50-10:35: Legislative Implementation Presentations

o 9:50–10:00: Resilience Improvement Districts

o 10:00–10:10: Stormwater Authorities

o 10:10–10:20: Climate Change and Coastal Resilience Reserve Funds o 10:20–10:35: Question and Answers

10:35–10:45 Break

10:45–11:00: Keynote Address

11:00–12:00: Legislative Panel

12:00–1:00: Lunch

1:00–2:10: Resilience on the Ground and In the Water Panel

2:10–2:30: Networking

Since space is limited, registration will close on November 10, 2026.

Please join us to work toward a more Resilient Connecticut!

EVENT WEBSITE

For more information and

I tried all common troubleshooting steps: deleting cache reinstalling different settings turning off adblocker/vpn disabled efficiency in task manager and set it permanently to off in FF

I used to have 1000+ tabs in 2016 no issue. I had problem in past with Firefox using 100% CPU which now it is not using only like 50, but memory is getting full 89% i use also large page file on ssd. Problem is even when i restart firefox it is slow with low RAM usage! SO that's not it! Even 5 tabs sometimes it is slow!

It is so damn slow it drives me crazy! I tried also Quantum in past when Firefox has 100% CPU usage bug and it was only tiny bit better but still caused 100% CPU usage!

All other browsers are anti user cannot even stop Autoplay literal terrorist Firefox is only normal browser unfortunately performance compare to 2016 got absolutely abysmal! I had this problem even in-between reinstals of OS so it doesn't seem it is me. I play demanding games no issues on my PC...

Any time I try to load a webpage on Firefox, I get the error which states "Firefox can’t connect to the server". This occurs when the DNS over HTTPS setting is set to 'off' or 'default'. When the DNS over HTTPS is set to 'custom', the error displayed is "Firefox can’t protect your request for this site’s address through our secure DNS provider. Here’s why: Firefox wasn’t able to connect to firefox.dns.nextdns.io." (it's the same for next DNS or cloudfare).

When I initially opened the DNS over HTTPS settings, this message was displayed: "DNS over HTTPS is not working because we encountered an error (NS_ERROR_CONNECTION_REFUSED) while trying to use the provider Cloudflare". However, this message went away and I have not been able to replicate it.

I have already tried everything suggested in the support article "Firefox can't load websites but other browsers can". I do not have any antivirus software installed. I reconfigured the proxy settings to no proxy. I changed the IPv6 settings. I changed the DNS Prefetching settings. Nothing has worked.

Safari works perferctly fine, Chrome is giving me similar errors.

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.

Does Firefox VPN not work with DNS over HTTPS set to Max Protection, and when using a custom provider?

With the VPN on and DNS over HTTPS set to Max Protection set to custom provider, no pages will load and I get an error screen/can't connect to proxy screen.