It does autoplay on Firefox, but not on Chrome. That maybe because of Chrome's Autoplay Policy changes.
I see your X theme and Cornerstone is not in compatible version, please update both to the latest version (X 6.4.4 / CS 3.4.4)
Updating Your Themes and Plugins
Remember to clear all your caching features (plugin, server-side, CDN, and browser's cache) after updating so that the code from the latest release is always in use. This will help you to avoid any potential errors.
Hope it helps,