Step 4: Set the delivery policy for the subscription (optional) - Amazon Simple Notification Service
Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Step 4: Set the delivery policy for the subscription (optional)

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.