SAP Message UCFE266 - Value input not possible due to first data entry for year/period &1/&2

Diagnosis
Posting and data entry can be blocked for anitem and atransaction type. The dataentry layout must check whether the cell is blocked for the year &V1&and period &V2& of first data entry.

Procedure
Check the blocking of posting and data entry of the relevant item andtransaction type, and also the year and period of first data entry forthe consolidation unit.