Planning characteristic &3 is not intended for characteristic planning

What causes this issue?

You have selected the enhancement "Characteristics Planning" for
planning layout &V2& (planning step &V1&). Characteristic &V3& for
which planning data is to be created, is not a classification system
characteristic.

System Response

The planning scenario cannot be activated due to the inconsistent data.

How to fix this error?

You have the following three possibilities:
In the details screen for planning layout &V2&, deactivate enhancement
"Characteristics Planning" .
In the details screen for the planning layout, enter a different
planning characteristics for which planning data is to be created.
On the "Special Planning Levels" screen, indicate that planning
characteristic &V3& is a classification system characteristic.
When you have done this, check the planning scenario again.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.