If the System Account for a posting is not linked, the transaction will fail. The following two error messages are the common where these are not configured.
The System Account has not been configured at all
This may require a new account in order to linked
The System Account has been configured at the Global Level – to the Master Accounts – but the Account is not active in this division. The warning should show the account id of the missing account.
To fix: Go to the accounts list, click edit, on the left hand side of the list is the account ID – find the account, select as active in the division.