Firefox Community Forum

For the pas 2 mouths i am getting random: "Server Not Found.Firefox can’t connect to the server at" It is happening on random sites that i know for sure they are not down... Waiting , closing fire fox and open it again, refresh but after waiting... helps.

My Firefox on a Linux system only connects to my gmail acount. Any other attempt to connect to sites gives the msg Can not connect to Server. Do I need to reset something? Or reload the Linux system. Thanks Graham Benson

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.

Hi, I don't know what is causing this issue but I cannot click on links (on desktop) from my emails it just takes me to a blank page that can't load saying Server not found. I can click on the links using my mobile app. Is this a Firefox issue?

I have tried with Firefox and Waterfox, (I don't use Chrome, Edge etc). I am using gmail.

Hi. I have a Dell Inspiron, it’s a few years old, and my computer is running windows. Today I was on a website, doing my assignments as usual when randomly the internet stopped working on the browser (I was on the web for about an hour before this). There was no change to my behavior, I had been on the same site for the whole hour, and had been interacting with the site during that time. My computer still says it’s connected to the internet, and I was even able to play an online game on my computer that I had downloaded, so it looks like my computer is connected to the internet. I’ve tried to clear my cache and open private windows but that didn’t help.

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?

I am trying to be nice but it's should be going both ways . Server Not Found. Firefox can’t connect to the server at www.rebaid.com. AND YOU GIVING ME ADVICE: "Try connecting on a different device. Check your modem or router. Disconnect and reconnect to Wi-Fi." We both know that my router is not the problem nor my PC/device. It's you and you should harder to connect me with a page-site.

I asked a question last night about whether or not Firefox had an IP Address. Sounded silly, but I was dealing with an unfamiliar IP. I did eventually find apps that locate IP Addresses. Problem solved . Just want to thank James for taking the time to respond to my question.

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.

I'm a beta update channel user, so this may not reflect what 'normal' users are seeing. I use Firefox in Linux, debian v13, so normal people that are using Windows or MacOS also might not see the changes I'm asking about? -- I have no way of knowing.

Anyway: in FF v152.0b6, the "Connection Settings" area seems to have disappeared entirely from the settings menu. I used this area of the settings frequently.

The ability to set proxy still exists in the about:config settings area. In the future, will about:config be the standard place to go for people that want to manually set (or toggle) an http/https proxy?

Thanks for reading, and thanks to all the Volunteers who make this place and Mozilla software function. I use your stuff all day, every day, and my life is better because of it.

Why can't I open?

https://water.weather.gov/ahps2/hydrograph.php?gage=porm2&wfo=lwx

This is what I get: Server Not Found

Firefox can’t connect to the server at water.weather.gov 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…

Issue Summary: When disconnecting from a corporate Cisco AnyConnect VPN on macOS, Firefox completely loses its internet connection and throws network errors. Other browsers (Chrome, Safari, Edge) continue working perfectly on the home network. Standard troubleshooting steps—like clearing Firefox's DNS cache, changing proxy settings to "No Proxy", turning off DNS over HTTPS (DoH), and flushing system DNS—do not resolve the issue.

Root Cause: Cisco AnyConnect locks low-level socket configurations and routing rules within the active Firefox user profile (prefs.js). Even after the VPN is disconnected, Firefox remains bound to the dead corporate pipeline, a behavior that standard settings menus cannot override.

Proven Solution: The only way to clear the corrupt VPN socket locks is to completely reset the internal profile architecture:Open Firefox, type about:support into the address bar, and press Enter.Look at the top right of the page and click the "Refresh Firefox..." button. Accept the prompt. Firefox will close, securely back up your bookmarks/passwords, generate a fresh profile, and restart.Internet access will instantly return to normal. (Note: You will just need to reinstall your extensions afterward).

As described, firefox is entirely not working for any website. This happened after my computer crashed (hardware problem) and I restarted twice, but could be related to a firefox update that was waiting for me to restart.