Characteristic & does not exist in planning area &

What causes this issue?

Characteristic &v1& has not been assigned to planning area &v2&.

How to fix this error?

Characteristics are assigned to planning areas via planning object
structures. If you have the necessary authorization, assign
characteristic &v1& to the planning object structure that has been
assigned to planning area &v2& in S&DP Administration. Otherwise
contact the person responsible for the administration of planning area
&v2&.
Alternatively you could use another characteristic that has been
assigned to planning area &v2&.

Error message extract from SAP system. Copyright SAP SE.