Subject: Follow-up on missing INITIAL_BUY notification (transactionId: XXX) Hi, thank you very much for your support. I’m following up regarding the missing INITIAL_BUY notification we encountered. We attempted to use the Get Notification History API to verify whether the notification was sent for the relevant transactionId. However, the transaction took place more than 180 days ago, so the API does not return any data for that time range. We’ve also double-checked our server logs and found no record of receiving a SUBSCRIBED notification with subtype=INITIAL_BUY. That said, we did receive subsequent notifications (such as DID_CHANGE_RENEWAL_STATUS and CANCELLATION) for the same user, and also received INITIAL_BUY notifications for other users without any issues. Our system appears to have been fully operational at the time and was likely processing all other notifications correctly. If there's any other way to confirm whether this notification was sent — or if you're able to check on your end — we would greatly appreciate it. Thanks again for your assistance!