Check the device (the accessory triggering the warning) is within range of the Yale Smart Alarm Hub.
If you are still receiving warnings you can disable supervision for the one accessory that is triggering the warning, although we do not recommend this.
Supervision mode activates a notification if any devices lose connectivity with the Yale Smart Alarm Hub. To deactivate Supervision mode, in the Yale Home app, open settings for the specific device, scroll down to Supervision Mode, and slide the setting off.