You are trying to reverse Supplier Invoice to previous period.
Error C+803 happens:
"Updating values for material &1 &2 is not possible".
SAP S/4HANA Cloud
Reproducing the Issue
Reverse Supplier Invoice to previous period.
The relevant material has status "Closing Entries Completed" for material ledger in previous period.
It's not allowed to make posting to previous period anymore.
You can do the reversal to current period.
Or you can reverse the post closing for material ledger for previous period and do the reversal again.
C+803, C+ 803, updating, invoice, previous period. , KBA , CO-PC-ACT , Actual Costing , Problem