A posting rejection is usually a period-control issue, not a document-date mistake. The journal entry date is the document issue date, while the posting date determines the posting period that the system checks. The posting period variant, not the fiscal year variant, opens and closes periods for the header and for each account type.
SAP S/4HANA / posting date / document date / posting period variant / fiscal year variant / period control / authorization / FI document
In SAP S/4HANA, a payment to a vendor settles an existing liability from a posted invoice; it is not a new expense. Tracing the payment back to the original invoice is done using clearing documents, assignment fields, and line item displays.
SAP S/4HANA / Accounts Payable / Financial Accounting / Clearing / Document Flow / FI-AP
A practical order for comparing SAP reports: organizational scope, ledger, fiscal period, currency and line-item detail.
SAP / Universal Journal / Reporting