Notifications
Browser notifications tell you about incoming calls and messages when Connect isn't the window you're looking at. This section turns them on, and gives you a test button so you can check they come through.
If notifications are blocked
Connect asks for notification permission the first time you use it. If you blocked or dismissed that prompt, Connect can't ask again, so you'll need to allow notifications in your browser settings instead. Google's notification settings article covers where to find them in Chrome.