If you schedule the payment to be executed at a future date, you should ensure that your account’s balance will be sufficient on the payment date.
In order to be sure, you can choose to block the amount in your account (without interest loss) when you submit the payment order.
You can receive notifications of unsuccessful transactions (those that failed to be executed) via the Alpha Alerts service, provided you have activated the service from Services > Alpha Alerts > Electronic Banking Transactions.