First, ensure you are connected to the correct station in the FieldKit app.
If the data from the station still isn’t updating, make certain that you’re still connected to the station’s WiFi access point in your phone settings.
If you are connected, press one of the buttons on the upper board to wake the unit up, then go into the readings menu and see if the numbers match those you’re seeing in the app. If not, try restarting the station using Tools> Reboot> Yes. Then reconnect to the station and see if you can now see data in the app that matches what’s in the readings menu.