API Key for customerReviewResponses

We're trying to test submitting a review response through the App Store Connect API. The documentation states that an API key with the role App Manager should allow this. However when testing I get a 403 response with the error:

{
    "errors": [
        {
            "id": "15eb1546-78e2-45a6-b1f4-3cc96166b5fb",
            "status": "403",
            "code": "FORBIDDEN_ERROR",
            "title": "This request is forbidden for security reasons",
            "detail": "The API key in use does not allow this request"
        }
    ]
}

Can anyone tell me where I'm going wrong? According to the documentation the API key should work.

API Key for customerReviewResponses
 
 
Q