There is a set of logic built into Kiip to simulate a serendipitous offering of rewards. For example, there is a minimum time requirement between moments in order for the second moment to be eligible for a reward. Additionally, there's usually a limit to the number of rewards any one person can redeem in a day. This helps to increase the engagement rates in your app and doesn't spam users.
If you’re saving a moment and no reward is showing, it’s most likely that there are no rewards available for that specific moment. If the call returns a null poptart, then the moment save was successful. If there is no callback, something might be wrong with your moment call. Make sure you double-check your moment call in your codebase and ensure that you are passing the correct app_key and app_secret to Kiip.
You can obtain your app_key and app_secret during the onboarding flow when adding an app to Kiip. If you've already submitted your app to Kiip you will find this information in your app's dashboard.