this fixe worked for me :) thank you!

Hi

I appreciate that you may have done this already, but please can you restart Firefox which should resolve this issue.

Earlier today, Firefox became unresponsive due to a change in defaults by a cloud provider which triggered a Firefox HTTP/3 bug. We disabled the configuration change and confirmed this fixed the issue.

I have my FF updated to 96.0.1 Still can't get to Facebook, Youtube, other sites. I tried the network.http.http3.enabled to False. Rebooted Firefox and the computer. Still won't work. Mickysoft Edge works fine. My other windoze computer has FF 95.0.2. It still works fine. Turned off Auto Update on both computers. Luckily I caught it before it auto updated FF. I hate it when I hear "My computer isn't working. You were the last one to use it. What did you do to it? I need it NOW". And I look like an idiot. Then I have to waste 2 hours troubleshooting the computer that I didn't break. Then find the "workaround" that doesn't work. How about an email saying "sorry we broke your computer. If it isn't fixed, do this".