When asynchronous postback failures occur within SWP Checkout 2.0, the system attempts to resend the response if the post action did not result in an HTTP 200 response (i.e., OK). The number of retry attempts depends on the actual error (e.g., transaction error vs. an endpoint connection failure).
For each failed postback attempt, the system adds one minute to the retry time. For transaction errors, the system will attempt to retry up to twenty times. For endpoint connection failures, the system will attempt to retry up to ten times.