Google’s recent update prevents Chrome playback video and audio files from playing until a user interacts with the domain (click, tap, etc.) For Digital Signage this means, your videos would not work until you plug in a mouse and click on the screen. Please note, as of August 2019, Google has pushed an update to Chrome OS that now allows the Autoplay policy by default for any devices managed by a Chrome Device Management license. You should not have any issues with video or audio playback on your devices managed by these licenses. If you're not using a Chrome Device Management license, your device will not be able to playback video and audio files automatically.
You can learn more by clicking here to view Google's support article on Autoplay policy information.
The original Autoplay policy update limiting video and audio playback was released in early in May 2018. This would restrict devices from video and audio playback automatically unless the Autoplay policy settings were changed according to the instructions found in this article.
As of August 2019, Google released a new update that automatically allows the Autoplay policy for videos and audio files for devices managed with Chrome Device Management licenses automatically. Unmanaged devices no longer have access to Autoplay policy settings.
Steps on how to change the Autoplay Policy for Chromebit, Chromebox, Chromebase and Chromebook devices