We have configured HTTPS URLs for both Sandbox and Production in App Store Connect. These URLs are different for Sandbox and Production environments. We have created a Signed JWT and tested the notification feature in our dev environment with the Sandbox configuration, and it worked successfully. However, when we tried the same with the Production configuration, our server was unable to receive the notification.
Our app is already live, and we have integrated consumable in-app purchases. Recently, one of our QA testers purchased a product and requested a refund from Apple support. Unfortunately, our server did not receive any notification from the app store about the refund, and we are unable to debug the issue.
We would like to inform you that our server is TLS 1.2+ compliant, and we have properly configured an SSL certificate.