User receives a closed accounting period error when attempting to update a vendor bill, even though the current accounting period appears to be open.
This happens when the vendor bill date falls within a locked accounting period. In this case, the vendor bill was dated January 1, 2025, and the January 2025 accounting period was locked, which prevented any updates to the bill.
To resolve this issue, temporarily reopen the January 2025 accounting period, update the vendor bill date to January 1, 2026, and then re-close the January 2025 period. After the vendor bill date is moved out of the locked period, the update completes successfully.