SAP Message UCF6139 - Task &1: Document type &2 cannot be used

Diagnosis You want to use document type &V2& in task &V1&. This is not possiblebecause this document type is already defined as the document type forthe historical posting mode on the Legacy Data Transfer tab pageunder Selected Items. Procedure Either change document type &V2& in task &V1&, or use a differentdocument type for the historical posting mode on the Legacy DataTransfer tab page under Selected Items.