I uninstalled Firefox and then downloaded the latest version. When I tried to log in, I found that clicking the login button didn't respond, which led to the inability to log in! I logged in successfully using the troubleshooting mode. However, when I used a vpn to access some websites like github (i am a student in china), the login status dropped and I needed to log in again. But at this time, clicking the login button didn't respond. I hope this problem can be fixed. Otherwise, if I can't log in and use the vpn, I will have to try using other browsers. But I really like Fiefox! Thanks!