Shipping API V2/V1

[melbin2827]

I want to get tracking information for a particular order through the API call

https://sandbox.sellingpartnerapi-eu.amazon.com/shipping/v2/tracking?trackingId={trackingId}&carrierId={carrierId}

I tried running this on Postman with the right trackingId, CarrierId and passing the Access Token in header as
x-amz-access-token .....

But I end up getting this error

{
"errors": [
{
"code": "Unauthorized",
"message": "Access to requested resource is denied.",
"details": ""
}
]
}

Even though the values are right. What might be going wrong, Any and all help would be appreciated