To fix this error when starting the threhsold. Please de-check the "Not Exist" checkbox on the Threshold Condition window.
The "Not Exists" checkbox is used to trigger alerts when NO data is returned for a particular where clause. This means that we cannot use fields in the On Event or Off Event text.
More information about the threshold configuration can be found here:
https://help.prognosis.com/prognosis/118/system-functions/thresholds/threshold-condition-properties-...
