Why it is not able to post to a customer a/c in a previously closed 'Period'? | SAP-FICO

 When you want to selectively 'close' or 'open' posting period of some accounts (account range), here will be no problem with that if you are doing it for GL accounts. But, if it is a sub-ledger account (like the customer), the same has to be achieved via opening or closing the account interval of the 'reconciliation' of that account type.