Troubleshooting : Speaker not responding
Short answer
This article troubleshoots issues with the Marshall Acton Multi-Room functionality if it's unresponsive.
If your Speaker is not responding, then the likely cause is a software problem has occurred - there are several troubleshooting options you can attempt to resolve this:
Unplug the Speaker power plug from the wall socket, wait for 15 seconds. the plug it in again.
Reset the Speaker to its factory state.