TestStep mutation response with an error

[johipsum]

{
    "errors": [
        {
            "message": "The provided key element does not match the schema",
            "locations": [
                {
                    "line": 5,
                    "column": 5
                }
            ],
            "path": [
                "testStep",
                "service"
            ]
        }
    ],
    "data": {
        "testStep": {
            "id": "ciy0jidbmaivt0133sqdy35e6",
            "description": "Triggers a flow run with a given url",
            "service": null,
            "result": null,
            "error": null,
            "tested": true,
            "__typename": "StepTestType"
        }
    }
}