Why can't I post into a closed month?
Ordinary posting requires an open period; reopening is separate from changing a draft.
A closed or locked period rejects ordinary posting for its dates. This can affect invoices, bill approvals, payments, bank postings and General opening imports. Someone with Manage fiscal periods (close/reopen/lock) permission can reopen a closed month with a recorded reason; a locked month has no reopen action. A closed General year also blocks ordinary journals, even without monthly periods. Reopen the year before posting. Backdating settings still apply afterward. Ask the person responsible for the books to review the intended correction. See Reopen a fiscal period.