What happens if a transaction is not authorized during the payment process?

When a transaction is not authorized during the payment process, it is typically declined. This means that the payment processor has not received the necessary approval from the customer's bank or card issuer to complete the transaction. Authorization is a critical step in payment processing, as it ensures that the customer has sufficient funds or credit available and that the transaction details are valid. If the authorization fails, the payment cannot proceed, and the transaction is effectively halted, preventing any funds from moving from the customer's account to the merchant. This protects both the customer from unauthorized charges and the merchant from potential losses.

The other options do not accurately reflect the typical outcomes of a declined transaction; for example, if the transaction is declined, the funds do not move, so there is no automatic return, the merchant does not receive payment, and customers are usually alerted through the payment interface rather than through email.