Downlink ACK Message

If you ask a confirmation when you send a downlink, you should receive the following message.

{
    "DevEUI_downlink_Sent": {
        "Time": "2019-08-22T16:48:02.000+02:00",
        "DevEUI": "0018B20000000D48",
        "FPort": 1,
        "FCntDn": 47,
        "FCntUp": 39,
        "Lrcid": "0000000F",
        "SpFact": 7,
        "SubBand": "G1",
        "Channel": "LC2",
        "Lrrid": "FF0106DE",
        "DeliveryStatus": 0,
        "DeliveryFailedCause1": "B0",
        "DeliveryFailedCause2": "00",
        "DeliveryFailedCause3": "00",
        "CustomerID": "199983788",
        "CustomerData": {
            "alr": {
                "pro": "ADRF/DEMO",
                "ver": "2"
            }
        },
        "TransmissionSlot": 1,
        "Frequency": 868.3
    }
}