Getting 401 Unauthenticated when calling StoreKit In-App API with JWT

Hello, I am trying to call the StoreKit In-App API, but I am consistently receiving a 401 Unauthenticated error. Here is what I have done so far: JWT creation (via https://jwt.io): Header: { "alg": "ES256", "kid": "**********", "typ": "JWT" } Payload: { "iss": "********-e662-43d2-be42-012d0138ce39", "aud": "appstoreconnect-v1", "iat": 1757389187, "exp": 1757390987 } Private Key (.p8): -----BEGIN PRIVATE KEY-----


-----END PRIVATE KEY-----

Algorithm used: ES256

This generates the JWT successfully.

API Call:

I then include the JWT in the request header as follows: Authorization: Bearer ************ Endpoint: https://api.storekit-sandbox.itunes.apple.com/inApps/v1/transactions/2000001003740262

Response: Status: 401 Unauthenticated Request ID: S3KCYHDVRMDKUT3TZVTY3QRRWM.0.0

Has anyone else faced this issue?

Is there something incorrect with how I’m generating the JWT (e.g., iat/exp values, formatting, or encoding)?

Do I need to generate separate keys for Sandbox and Production, or is the same key valid for both?

Any guidance would be appreciated. Thanks in advance!

Getting 401 Unauthenticated when calling StoreKit In-App API with JWT
 
 
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