There has been a change in the Chrome browser (v66+) related to videos that autoplay. The browser will now force any auto-playing content to begin muted.
This, in theory, helps a viewer decide what content on the page they wish to focus on. This 'auto-mute' behaviour may change over time, depending on how the viewer interacts with videos on the domain (i.e. how often do they unmute).
The current workaround to avoid the 'Click to Unmute' message and the muted audio is to disable autoplay for the player. This can be done in the Player Settings, but in some cases, you may need to remove this from the URL or player embed code, written as 'autoplay=1'