Which browser should I use?

In general, Google Chrome works best and Safari works worst. Opera usually doesn't encounter many problems and users have reported good experiences with Firefox. In any case it is always a good idea to use the most current browser version available.

But in short, if you're stuck, try Chrome (or gladly also the Open Source variant Chromium).

(Jitsi is based on webRTC, which is not supported by older browsers)

Alternatively there is also the App Jitsi-Meet for OSX and Windows: https://github.com/jitsi/jitsi-meet-electron/releases

And Jitsi Meet for iOS:    Jitsi Meet     and Android:    Jitsi Meet