SAP Message USMD1535 - Data model &1, entity type &2: Invalid use in hierarchy

Diagnosis The hierarchy for entity type &V2& has an additional entity type &V3&that uses the setting #&V4&# and does not have external key assignments.However, entity types with the setting Hierarchy Name orRanges on Node Level Allowed must have external key assignments. System Response The system cannot activate data model &V1&. Procedure Change the type of key assignment for entity type &V3& or select adifferent entity type (instead of Hierarchy Name or Ranges onNode Level Allowed) in the hierarchy for entity type &V2&.