Message SAP WV236 - No plants exist in plant group &1

Diagnosis
No plants are assigned to plant group &V1& in the classification system.
Or:
No sites are assigned to an promotion-internal site group.
Or:
In the reassignment of sites with the BAdI WRF_PLANT_MAPPING, no validvalues could be determined.

System Response
Prices cannot be calculated for plant group &V1&.

Procedure
Check plant group &V1&.