If you visit any Livestream account's profile page, you may see an event indicating that it has started.
However, when you click on the event, instead of live content, you see this message instead:
This is because Event Started indicates that the event is within the timeframe which the owner of the event set for it to start and end. The stream does not start until the event owner manually begins pushing a stream to their Livestream event page.
When the event is live, the live player will load in the event automatically (allow 30 seconds for the player to load). The profile page will switch to saying Event Started to Live Now.
Also, be sure to check the Posts drawer to see if the event already streamed and is now finished. Oftentimes, event owners will post the ideo-on-demand of their stream immediately after it ends and you can play it back at any time.