Cloudflare captcha? Does such thing exist? They have Turnstyle which I never had problems on my computers (only Firefox installed). I did have problems on a niche phone running an outdated mobile Firefox, but I believe they might have been solved.

Edit: Yes, seems to work now. After I complained on HN earlier their CTO asked me to send a trace. I did so and a couple of months later the problem was gone. Whether that was causal or incidental I have no idea.

I have never encountered this and i have been using firefox daily since 2008. So confused lol