SAP Message WXP081 - Character. &2 cannot be used as "Classification System Characteristic &1"

Diagnosis
You have assigned "Classification System Characteristic" &V1& toplannning characteristic &V2&. You have not, however, entered thecharacteristic from the classification system that you want theplanning characteristic to represent.

System Response
The planning scenario cannot be activated because some requiredinformation is missing.

Procedure
In the "Special Planning Levels" screen for planning characteristicV2, enter the relevant classification system characteristic.
When you have done this, check the planning scenario once again.