There are a couple of reasons why your Temp Stick may have lost connection. Follow these troubleshooting steps to help get your Temp Stick back online:
We recommend using Energizer Ultimate Lithium AA batteries.
WiFi equipment, network name or WiFi password has changed: Follow these steps to update your WiFi information.
WiFi signal is too weak/far away: Try moving the temp stick closer to your router and see if it begins checking in again. You can also had WiFi extenders to your network to help extend your signal to harder to reach places.