How "Subscription Status URLs" works for Apple. In-app purchase (automatically renews)

Question

Does anyone work on subscription status status and how it works to automatically resume in-app purchases in sandbox mode

When I try to achieve this, I can subscribe to my product from the application, but when checking the subscription status on the server (s), we do not get any "statusUpdateNotifications" from Apple Server. We have tested our URL and this is in compliance with Apple’s safety standards.

We went through the link below, but did not get much information.

Work with Subscriptions