As of right now, Twitch seems to be down. In a brief statement made over Twitter, Twitch said it is "investigating an issue that is causing the site not to load properly." There is currently no update on when the issue may be fixed.
If you log onto Twitch right now, you're able to load the homepage fairly easily. However, trying to watch a livestream will likely just bring up a black screen. It doesn't matter whether you're subscribed to the channel or not--currently, all of Twitch seems to be unwatchable. Chat isn't working either.
🔎 We are investigating an issue that is causing the site not to load properly. We will update you when we know more.
— Twitch Support (@TwitchSupport) April 27, 2020
Just prior to this, Twitch went down for scheduled maintenance. Starting on April 27 at 3 AM PT / 6 AM ET, certain Twitch channels were unable to go live or their broadcasts were simply not available. Twitch has not announced whether there is any direct correlation between the scheduled maintenance and today's issues.