With Mac's latest security updates to Mojave, you may have to enable Chrome camera access from your security preferences.
1. On your Mac, go to System Preferences.
2. In the System Preferences window, click Security & Privacy.
3. In the Security & Privacy window, click the Lock (bottom left), so you can make the following change.
4. Click Camera, then make sure Chrome is checked (right side).
5. Close Security & Privacy, and try re-entering the Evercast room. You may have to restart Chrome for the new settings to save.