The browser broadcaster is based on WebRTC. While the technology still has issues, it is reportedly working well on Chrome for Mac, Windows and Android.
We have not properly tested it yet in either Firefox, Safari or Opera and there is no proper support for the technology in Edge/IE.
One may also encounter connectivity issues due to NATting, UDP ports being blocked and other networking twists.
All in all, while this works great for many, it will just not work for some. We are slowly improving on it but given the underlying technology it will probably never be perfect.
Recommended you consider an RTMP broadcasting solution if it’s not working for your setup.