Before an event can start, access must be granted to a camera (if video) and a microphone. Every browser does it differently, but you will not be able to broadcast your first event without giving permission.
How it looks on Chrome
The permission will be asked again next time, unless you allow the browser to remember your choice.If the browser doesn't ask for permission and you are able to start an event, it might because it has been allowed already in the past. Everything is fine.
If the browser doesn't ask for permission and you are not able to start an event, it might be because it has been denied in the past. You will need to go in the settings to allow access to the camera and microphone.
How to do it on Chrome and Firefox.