What happens if my server misses a notification?

We try again. A failed notification is retried several times over about four hours, and every attempt is listed on your Postback log page with what your server answered.

If your server was down for longer than that, use your Conversions page or the API to find what you missed. You can look up any completion by the transaction id we sent.

Your server should answer with a success status within a few seconds, even for a transaction it has already handled.