Step 4: Optional - Set the delivery policy for the Amazon SNS subscription

By default, if the initial delivery of the message fails, Amazon SNS attempts up to three retries with a delay between failed attempts set at 20 seconds. As discussed in Step 1, your endpoint should have code that can handle retried messages. By setting the delivery policy on a topic or subscription, you can control the frequency and interval that Amazon SNS will retry failed messages. You can also specify the content type for your HTTP/S notifications in DeliveryPolicy. For more information, see Creating an HTTP/S delivery policy.