I have a module that works fine when played locally in Safari, and works fine when played in Chrome. However, when played back through Safari (latest version=11.1.2), none of the videos load which causes the player to not work.
There's a few things you may have to do in Safari due to recent updates around autoplaying of content.
1 - Safari > Preferences > Websites > Allow Autoplay
2 - Safari > Preferences > Privacy > Uncheck "Prevent Cross-Site Tracking"