On the front of the devices there are four LED which can give you information about the status of the device.
The four LEDs are the next:
light is on, if device is connected to power supply and turned on
light is on, if the device is connected to network
light is on, if internet can be accessed (successful heartbeat to Dension Sherpa)
light is on if operating normally, light is off if not playing content, slow blinking (0.5Hz) means the device is playing from fallback source, fast blinking (2Hz) means the device is in limited mode, very fast blinking (10Hz) means the device encountered an error and is not playing, but according to the current settings it should