To resolve issues playback issues on Safari, please firstly make sure you have updated to the latest version of Safari (version 11 or greater). 

Using the latest version of Safari and still having issues? Please follow the steps below to enable Auto-play: 

1. Navigate to in Safari. 
2. From the main Safari menu, select "Settings for this website". 
3. There is an option for Auto-Play. Please set this to “Allow all autoplay”. 
4. Load any video and this should resolve the playback issue.