Setup: macOS Tahoe (26.4) and Firefox 149.0

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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?

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.

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?

Apr 3, 2026, 04:18 CST

In the last 48 hours I haven't been able to access the following - https://www.co-operativebank.co.uk - they do not appear to be the problem - when I try the link the 'retrying' symbol on the top left of screen (?taskbar), flashes extremely rapidly and it appears the system can't find the website. Are you aware of this issue.

Firefox is causing my wifi adapter to shut down

Running firefox for any length of time will shut down my wifi adapter at a random moment. The only solution is reboot

Using opera, the problem does not occur, I can run opera continuously without problem. Running firefox at anytime will cause the fail at some point.

Im running windows 11 I have run firefox in safe mode Disabled all addons Set to “No Proxy” Disabled power saving on the adapter Replaced firefox with the ESR version 140.8 , previous version was the latest I note that there are up to 11 firefox process instances in task manager (all cleared when firefox is shut down) Firefox is set to update automatically Several updates have occured during this problem Disabled hardware acceleration Cleared cache Latest wifi driver And a few more that I cant recollect at the moment

Running out of hair to pull out

Any idea’s?

Firefox 147.0.4 on macOS 26.3 does not work via SOCKS proxy.

Firefox 147.0.4 on Windows 11 x64 works fine via the same intranet SOCKS proxy, with exactly the same settings.

The advantage of Firefox is its flexibility. It supports its own SOCKS proxy settings, independent of systems-wide ones. Unfortunately, it seems this Firefox feature is broken on macOS (but Windows version works perfectly).

Safari 26.3 (21623.2.7.11.6) and DuckDuckGo 1.177.0 (625) web-browsers that use system-wide macOS SOCKS proxy settings also works fine with this intranet proxy server. So it seems SOCKS proxy server itself is OK, and the problem is confined to Firefox on macOS.

Has anyone seen Firefox 147 on macOS work via SOCKS proxy? Is there a principal difference between how Firefox handles SOCKS proxy on macOS vs. Windows? What might be the best way to address the problem on macOS?

Thanks!

When I opened up Firefox this evening, websites stopped working if "DNS over HTTPS" is set to "Max Protection". In some instances, such as YouTube, the website loads, but it acts like you're offline and tells me to turn on my Wi-Fi even though it's already on and running fine. Weirdly, it seems that setting DNS over HTTPS to Max Protection, loading a website, set DNS over HTTPS to a lower setting, and then reloading the website fixes the issue, but it'd still be nice if we didn't have to go through the hassle at all. Thank you for your time and patience.

Sincerely, Watching Forests

So I started using Firefox on my older and newer laptops, but I've noticed that on my older laptop it has started giving me the message "You must log in to this network before you can access the internet", although I am already signed in on my Mozilla account there too. My newer laptop has had no issues for the record. Both systems are running windows 11, both have the same account that I am using, etc. If it makes any difference, my older laptop is using an ethernet cable whilst the newer one is connected via Wi-Fi. When I ran into this issue yesterday on my old laptop, the issue somehow resolved itself after I created a bugzilla account, although I am unsure if this was coicidence, so now I am confused why the issue has showed up again. Awaiting any kind of help or advice, thank you.

Moderator note: See also /questions/1551659 for a screenshot.

I own the domain name sabbathcalendar.com which is redirected to my website at sabbathcalendar.org. Firefox consistently gives the following message:

"Hmm. We’re having trouble finding that site. We can’t connect to the server at www.sabbathcalendar.com."

It doesn't matter how I enter the URL. When I simply enter "sabbathcalendar.com" in either Brave or Microsoft Edge, both browsers will immediately connect to my website at sabbathcalendar.org with no problem.

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.

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.