The server is running on Windows 10 PC, and I am displaying the clients on iPad Pro 11 (Safari), as well as Android phone (using Chrome). Still same issue. When launched directly from the Designer on the MyServer PC (default is Chrome), the volume slider seems to work fine, and also tracks with the volume up and down presses. But the slider and volume buttons don't track or sync together from the iPad or Android (they do work individually - i.e. volume up and down buttons work, but slider doesn't synchronize, or vice versa).