We've been approved for the Advanced Commerce API. After receiving the approval, we completed the initial setup requirements (submitted a generic product ID and shared our subscriptions page deep link).
When testing the Migrate Subscription to Advanced Commerce endpoint in the sandbox, we receive a 5000000 error.
What could be the reason/s for it? There is no information, and the API call we make includes all required parameters. Could it be related to the fact that our new generic product ID status is "Missing Metadata"? Is there a way to understand what the issue is on Apple's side?