question

Hello

I have a smart home skill which always gets HTTP 400 (INVALID_REQUEST_EXCEPTION: The request was malformed) when sending an ActivationStarted response after a DeferredResponse.

Then Alexa complains after 8 seconds that the scene is not responding.

I can't find any typo or mistake in my response.
Do you have any idea what could cause it?

Here are the requests I make/receive when activating a home scene using a voice interaction.

• Voice interaction: "Alexa Turn on...", Payload Alexa -> skill:

	
{
    "directive": {
        "header": {
            "namespace": "Alexa.SceneController",
            "name": "Activate",
            "payloadVersion": "3",
            "messageId": "4d4a5a20-57fb-4fe6-998d-1506667d20b2",
            "correlationToken": "AAAAAAAAAQ...bpnLQ=="
        },
        "endpoint": {
            "scope": {
                "type": "BearerToken",
                "token": "SAvQ6...NdVRa"
            },
            "endpointId": "a727ff14",
            "cookie": {}
        },
        "payload": {}
    }
}

• Synchronous response skill -> Alexa:

{
    "event": {
        "header": {
            "messageId": "9764a7e8-7000-48db-b1cb-c65b475eff49",
            "namespace": "Alexa",
            "name": "DeferredResponse",
            "payloadVersion": "3",
            "correlationToken": "AAAAAAAAAQ...bpnLQ=="
        },
        "payload": {
            "estimatedDeferralInSeconds": 1
        }
    }
}

• After about one second, Asynchronous response skill -> Alexa:

POST api.eu.amazonalexa.com/v3/events
Authorization: Bearer Atza|IwEBIMP...qWuKNg
Content-Type: application/json

{
    "event": {
        "header": {
            "messageId": "a924392f-fedb-49b4-99da-0b05aa68bd7b",
            "namespace": "Alexa.SceneController",
            "name": "ActivationStarted",
            "payloadVersion": "3",
            "correlationToken": "AAAAAAAAAQ...bpnLQ=="
        },
        "payload": {
            "cause": {
                "type": "VOICE_INTERACTION"
            },
            "timestamp": "2019-02-21T15:59:22.381232Z"
        },
        "endpoint": {
            "endpointId": "526cde62",
            "scope": {
                "type": "BearerToken",
                "token": "Atza|IwEBIMP...qWuKNg"
            }
        }
    }
}

• Error HTTP 400 from Alexa -> skill:

{
    "header": {
        "namespace": "System",
        "name": "Exception",
        "messageId": "333a8dff-f178-48a2-b19f-51460949c52b"
    },
    "payload": {
        "code": "INVALID_REQUEST_EXCEPTION",
        "description": "The request was malformed."
    }
}