Desktop browsers are now following Safari’s example of disallowing audio playback. Most notably is Chrome, which rolled out new autoplay policies in Chrome 66.
This is causing issues on major WebRTC platforms and may manifest as interface sounds no longer playing, audio visualizer failures, or your WebRTC application not playing sound from remote peers.
Specifically to Opentok applications, the audioLevelUpdated event and the animation for audio level do not work in Chrome 66. You can follow the chromium bug here: https://bugs.chromium.org/p/chromium/issues/detail?id=835767.
For more details on how the autoplay policy changes are affecting webRTC applications in general, please check out this article: https://webrtchacks.com/autoplay-restrictions-and-webrtc/.