What is the default number of retry attempts before a message will hard bounce?

The default number of retry attempts before a message will hard bounce is indeed set at 30. This configuration is designed to ensure that if the initial delivery of the email fails due to temporary issues, the email system will make multiple attempts to resend the message. Typically, this is implemented to account for situations such as server unavailability, network issues, or recipient mailbox overflow. The system will keep trying for a defined period, and after the specified number of retries, if the message still cannot be delivered, it will result in a hard bounce. This approach aims to maximize the chances of successful delivery while maintaining efficient use of resources in email processing.