Planning data already exists for ledger &

You want to copy data as a reference for your planning. However, data
already exists for ledger &V1&, record type 1 (planning), version &V2&,
company code &V3& and fiscal year &V4&.

System Response

How to fix this error?

Check whether you still want to create planning data in this area. You
should also make sure that existing data will not be overwritten by
mistake.

Error message extract from SAP system. Copyright SAP SE.