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?

I had a proxy set manually before and it was working just well, after I updated firefox it stopped asking for username password for my proxy and I keep getting no network error on every website I check. I also reentered the proxy data again and checked somethings in the about:config page to be true but still doesn't work.

seit einigen Updatesversucht das System verschiedene Webseiten ohne Erfolg zu öffnen. Es erscheint keine Fehlermeldung, auch kein Abbruch wegen Zeitüberschreitung oder der Hinweis, dass der Server nicht erreichbar ist.

HTTPS pages are no longer loading. Everything works fine in Microsoft Edge. I've reinstalled Firefox several times – the problem persists. Thank you very much for your help.

Hi, all experienced peoples are here I got strange issue with firefox lately. my site sometimes https://avsogirl.net/ not loads at all, just shows “server not found” look at the image.

i first thought maybe server down, but i checked with curl and ping, server responds fine. also tested same site in chrome and edge, loads normal there, no error. i tried clearing cache, disabling addons, even fresh profile. still same. only firefox gives this dns error.

i use dns-over-https in firefox, and i also have proxy config for work. maybe firefox handling dns/proxy different? when i switch off doh, sometimes page loads, sometimes not. so looks like firefox network stack problem, not site issue. anyone else facing same error?

The last few days I am unable to load websites that I regularly use. I get a cannot find error message. I have no clue what is going on. I turned off the vpn but that had no effect. This is really hindering my getting things done. Anyone with insight? I cleared the cash and cookies and all that, rebooted the browser as well as the desktop. Thanks

i have problem with setting up my proxy. i choose manual proxy configuration, fill the HTTP Proxy & port. When i click ok then input username & password but it keep asking for the username & password. (I have asked the proxy provider they say the proxy is good, no problem)

Mailfence.com is my email provider. I've been with them for years. Two weeks ago I am suddenly unable to connect with the website. My ISP is Comcast. My next door neighbor also uses Comcast. He can get to mailfence.com just fine. Can you please help with this issue. Comcast has declined to provide any help. Thanks.........Bob Horning