Check to see if the Puck is responsive by pushing and scrolling. If the Puck is not responding to button pushes or scrolling, try the unresponsive Puck troubleshooting steps.
Gateway Puck is Offline
If a Gateway Puck is offline, please check out the article on Gateway Puck WiFi Connection.
The most common reason a Sensor Puck goes offline is low signal strength. All Sensor Pucks need a good RF (radio frequency) signal to a Gateway Puck.
Check the signal strength. If the signal is low, try moving a Gateway Puck to a more central location - or closer to the offline device. You can also try converting the nearest Sensor Puck to a Gateway Puck, or adding an additional Gateway Puck to facilitate signal strength.
Also, try replacing batteries with fresh, new batteries. If you do replace batteries, wait 60 seconds before inserting the new batteries.
You can reset a Sensor Puck's connection to the nearest Gateway Puck by going into the Settings Menu and selecting "Unlink Gateway". Then enable Setup mode to discover and re-link the Sensor Puck(s).