Device sends ConfirmedUp but no UnconfirmedDown is initiated

Hello,

a Dragino LSN50v2 device using ABP auth and QoS1 / CFM tried to send a frame but did not get a confirmation.
This was an exception, as the following frame was properly confirmed.
How is that possible? How can I prevent that?

Here are the device logs. It tried 8 times, as usual for this device:

LSN50 Device
Image Version: v1.7
LoRaWan Stack: DR-LWS-005
Frequency Band: EU868
DevEui= 12 34 56 78 90 12 34 56
JOINED

Please use AT+DEBUG to see debug info

***** UpLinkCounter= 0 *****
TX on freq 868.500 MHz at DR 0
txDone
RX on freq 868.500 MHz at DR 0
rxTimeOut
RX on freq 869.525 MHz at DR 3
rxTimeOut

***** UpLinkCounter= 0 *****
TX on freq 868.100 MHz at DR 0
txDone
RX on freq 868.100 MHz at DR 0
rxTimeOut
RX on freq 869.525 MHz at DR 3
rxTimeOut

***** UpLinkCounter= 0 *****
TX on freq 868.500 MHz at DR 0
txDone
RX on freq 868.500 MHz at DR 0
rxTimeOut
RX on freq 869.525 MHz at DR 3
rxTimeOut

***** UpLinkCounter= 0 *****
TX on freq 868.300 MHz at DR 0
txDone
RX on freq 868.300 MHz at DR 0
rxTimeOut
RX on freq 869.525 MHz at DR 3
rxTimeOut

***** UpLinkCounter= 0 *****
TX on freq 868.300 MHz at DR 0
txDone
RX on freq 868.300 MHz at DR 0
rxTimeOut
RX on freq 869.525 MHz at DR 3
rxTimeOut

***** UpLinkCounter= 0 *****
TX on freq 868.300 MHz at DR 0
txDone
RX on freq 868.300 MHz at DR 0
rxTimeOut
RX on freq 869.525 MHz at DR 3
rxTimeOut

***** UpLinkCounter= 0 *****
TX on freq 868.300 MHz at DR 0
txDone
RX on freq 868.300 MHz at DR 0
rxTimeOut
RX on freq 869.525 MHz at DR 3
rxTimeOut

***** UpLinkCounter= 0 *****
TX on freq 868.300 MHz at DR 0
txDone
RX on freq 868.300 MHz at DR 0
rxTimeOut
RX on freq 869.525 MHz at DR 3
rxTimeOut

The corresponding ChirpStack frame log:

[
    {
        "uplinkMetaData": {
            "rxInfo": [
                {
                    "gatewayID": "MjUxMhQARgA=",
                    "time": "2021-01-04T13:13:35.262344Z",
                    "timeSinceGPSEpoch": null,
                    "rssi": -48,
                    "loRaSNR": 10.75,
                    "channel": 1,
                    "rfChain": 1,
                    "board": 0,
                    "antenna": 0,
                    "location": {
                        "latitude": 0,
                        "longitude": 0,
                        "altitude": 0,
                        "source": "UNKNOWN",
                        "accuracy": 0
                    },
                    "fineTimestampType": "NONE",
                    "context": "/OHL5Q==",
                    "uplinkID": "Dtii2DTURtSe4dgy7gnRWA==",
                    "crcStatus": "CRC_OK"
                }
            ],
            "txInfo": {
                "frequency": 868300000,
                "modulation": "LORA",
                "loRaModulationInfo": {
                    "bandwidth": 125,
                    "spreadingFactor": 12,
                    "codeRate": "4/5",
                    "polarizationInversion": false
                }
            }
        },
        "phyPayload": {
            "mhdr": {
                "mType": "ConfirmedDataUp",
                "major": "LoRaWANR1"
            },
            "macPayload": {
                "fhdr": {
                    "devAddr": "01821d8d",
                    "fCtrl": {
                        "adr": true,
                        "adrAckReq": false,
                        "ack": false,
                        "fPending": false,
                        "classB": false
                    },
                    "fCnt": 0,
                    "fOpts": null
                },
                "fPort": 2,
                "frmPayload": [
                    {
                        "bytes": "Lm0aI9IDshmWOmQ="
                    }
                ]
            },
            "mic": "9b9b387a"
        }
    },
    {
        "uplinkMetaData": {
            "rxInfo": [
                {
                    "gatewayID": "MjUxMhQARgA=",
                    "time": "2021-01-04T13:13:29.255855Z",
                    "timeSinceGPSEpoch": null,
                    "rssi": -48,
                    "loRaSNR": 10.75,
                    "channel": 1,
                    "rfChain": 1,
                    "board": 0,
                    "antenna": 0,
                    "location": {
                        "latitude": 0,
                        "longitude": 0,
                        "altitude": 0,
                        "source": "UNKNOWN",
                        "accuracy": 0
                    },
                    "fineTimestampType": "NONE",
                    "context": "/IYnDQ==",
                    "uplinkID": "/A1Svm3ZTKGkr8odmh9rIw==",
                    "crcStatus": "CRC_OK"
                }
            ],
            "txInfo": {
                "frequency": 868300000,
                "modulation": "LORA",
                "loRaModulationInfo": {
                    "bandwidth": 125,
                    "spreadingFactor": 12,
                    "codeRate": "4/5",
                    "polarizationInversion": false
                }
            }
        },
        "phyPayload": {
            "mhdr": {
                "mType": "ConfirmedDataUp",
                "major": "LoRaWANR1"
            },
            "macPayload": {
                "fhdr": {
                    "devAddr": "01821d8d",
                    "fCtrl": {
                        "adr": true,
                        "adrAckReq": false,
                        "ack": false,
                        "fPending": false,
                        "classB": false
                    },
                    "fCnt": 0,
                    "fOpts": null
                },
                "fPort": 2,
                "frmPayload": [
                    {
                        "bytes": "Lm0aI9IDshmWOmQ="
                    }
                ]
            },
            "mic": "9b9b387a"
        }
    },
    {
        "uplinkMetaData": {
            "rxInfo": [
                {
                    "gatewayID": "MjUxMhQARgA=",
                    "time": "2021-01-04T13:13:24.250648Z",
                    "timeSinceGPSEpoch": null,
                    "rssi": -49,
                    "loRaSNR": 12.5,
                    "channel": 1,
                    "rfChain": 1,
                    "board": 0,
                    "antenna": 0,
                    "location": {
                        "latitude": 0,
                        "longitude": 0,
                        "altitude": 0,
                        "source": "UNKNOWN",
                        "accuracy": 0
                    },
                    "fineTimestampType": "NONE",
                    "context": "/DnGHQ==",
                    "uplinkID": "Utm+i028SHG5I68Qisn+IA==",
                    "crcStatus": "CRC_OK"
                }
            ],
            "txInfo": {
                "frequency": 868300000,
                "modulation": "LORA",
                "loRaModulationInfo": {
                    "bandwidth": 125,
                    "spreadingFactor": 12,
                    "codeRate": "4/5",
                    "polarizationInversion": false
                }
            }
        },
        "phyPayload": {
            "mhdr": {
                "mType": "ConfirmedDataUp",
                "major": "LoRaWANR1"
            },
            "macPayload": {
                "fhdr": {
                    "devAddr": "01821d8d",
                    "fCtrl": {
                        "adr": true,
                        "adrAckReq": false,
                        "ack": false,
                        "fPending": false,
                        "classB": false
                    },
                    "fCnt": 0,
                    "fOpts": null
                },
                "fPort": 2,
                "frmPayload": [
                    {
                        "bytes": "Lm0aI9IDshmWOmQ="
                    }
                ]
            },
            "mic": "9b9b387a"
        }
    },
    {
        "uplinkMetaData": {
            "rxInfo": [
                {
                    "gatewayID": "MjUxMhQARgA=",
                    "time": "2021-01-04T13:13:18.244903Z",
                    "timeSinceGPSEpoch": null,
                    "rssi": -49,
                    "loRaSNR": 9.75,
                    "channel": 1,
                    "rfChain": 1,
                    "board": 0,
                    "antenna": 0,
                    "location": {
                        "latitude": 0,
                        "longitude": 0,
                        "altitude": 0,
                        "source": "UNKNOWN",
                        "accuracy": 0
                    },
                    "fineTimestampType": "NONE",
                    "context": "+94iHQ==",
                    "uplinkID": "cH1BInwwQkqJNc26YPnj9w==",
                    "crcStatus": "CRC_OK"
                }
            ],
            "txInfo": {
                "frequency": 868300000,
                "modulation": "LORA",
                "loRaModulationInfo": {
                    "bandwidth": 125,
                    "spreadingFactor": 12,
                    "codeRate": "4/5",
                    "polarizationInversion": false
                }
            }
        },
        "phyPayload": {
            "mhdr": {
                "mType": "ConfirmedDataUp",
                "major": "LoRaWANR1"
            },
            "macPayload": {
                "fhdr": {
                    "devAddr": "01821d8d",
                    "fCtrl": {
                        "adr": true,
                        "adrAckReq": false,
                        "ack": false,
                        "fPending": false,
                        "classB": false
                    },
                    "fCnt": 0,
                    "fOpts": null
                },
                "fPort": 2,
                "frmPayload": [
                    {
                        "bytes": "Lm0aI9IDshmWOmQ="
                    }
                ]
            },
            "mic": "9b9b387a"
        }
    },
    {
        "uplinkMetaData": {
            "rxInfo": [
                {
                    "gatewayID": "MjUxMhQARgA=",
                    "time": "2021-01-04T13:13:13.239048Z",
                    "timeSinceGPSEpoch": null,
                    "rssi": -48,
                    "loRaSNR": 11.75,
                    "channel": 1,
                    "rfChain": 1,
                    "board": 0,
                    "antenna": 0,
                    "location": {
                        "latitude": 0,
                        "longitude": 0,
                        "altitude": 0,
                        "source": "UNKNOWN",
                        "accuracy": 0
                    },
                    "fineTimestampType": "NONE",
                    "context": "+5HBBQ==",
                    "uplinkID": "Zyg+GubURe2cKsiw3KzQyg==",
                    "crcStatus": "CRC_OK"
                }
            ],
            "txInfo": {
                "frequency": 868300000,
                "modulation": "LORA",
                "loRaModulationInfo": {
                    "bandwidth": 125,
                    "spreadingFactor": 12,
                    "codeRate": "4/5",
                    "polarizationInversion": false
                }
            }
        },
        "phyPayload": {
            "mhdr": {
                "mType": "ConfirmedDataUp",
                "major": "LoRaWANR1"
            },
            "macPayload": {
                "fhdr": {
                    "devAddr": "01821d8d",
                    "fCtrl": {
                        "adr": true,
                        "adrAckReq": false,
                        "ack": false,
                        "fPending": false,
                        "classB": false
                    },
                    "fCnt": 0,
                    "fOpts": null
                },
                "fPort": 2,
                "frmPayload": [
                    {
                        "bytes": "Lm0aI9IDshmWOmQ="
                    }
                ]
            },
            "mic": "9b9b387a"
        }
    },
    {
        "uplinkMetaData": {
            "rxInfo": [
                {
                    "gatewayID": "MjUxMhQARgA=",
                    "time": "2021-01-04T13:13:08.233605Z",
                    "timeSinceGPSEpoch": null,
                    "rssi": -48,
                    "loRaSNR": 9,
                    "channel": 2,
                    "rfChain": 1,
                    "board": 0,
                    "antenna": 0,
                    "location": {
                        "latitude": 0,
                        "longitude": 0,
                        "altitude": 0,
                        "source": "UNKNOWN",
                        "accuracy": 0
                    },
                    "fineTimestampType": "NONE",
                    "context": "+0VgFQ==",
                    "uplinkID": "FJxclmi9Rw+7bOQsUY+i8A==",
                    "crcStatus": "CRC_OK"
                }
            ],
            "txInfo": {
                "frequency": 868500000,
                "modulation": "LORA",
                "loRaModulationInfo": {
                    "bandwidth": 125,
                    "spreadingFactor": 12,
                    "codeRate": "4/5",
                    "polarizationInversion": false
                }
            }
        },
        "phyPayload": {
            "mhdr": {
                "mType": "ConfirmedDataUp",
                "major": "LoRaWANR1"
            },
            "macPayload": {
                "fhdr": {
                    "devAddr": "01821d8d",
                    "fCtrl": {
                        "adr": true,
                        "adrAckReq": false,
                        "ack": false,
                        "fPending": false,
                        "classB": false
                    },
                    "fCnt": 0,
                    "fOpts": null
                },
                "fPort": 2,
                "frmPayload": [
                    {
                        "bytes": "Lm0aI9IDshmWOmQ="
                    }
                ]
            },
            "mic": "9b9b387a"
        }
    },
    {
        "uplinkMetaData": {
            "rxInfo": [
                {
                    "gatewayID": "MTUyNSoAKwA=",
                    "time": "2021-01-04T13:13:18.183500Z",
                    "timeSinceGPSEpoch": null,
                    "rssi": -117,
                    "loRaSNR": -17.75,
                    "channel": 0,
                    "rfChain": 1,
                    "board": 0,
                    "antenna": 0,
                    "location": {
                        "latitude": 0,
                        "longitude": 0,
                        "altitude": 0,
                        "source": "UNKNOWN",
                        "accuracy": 0
                    },
                    "fineTimestampType": "NONE",
                    "context": "5C/A9A==",
                    "uplinkID": "4kKYWKWTSJ+0qzhGYWdkNQ==",
                    "crcStatus": "CRC_OK"
                },
                {
                    "gatewayID": "MjUxMhQARgA=",
                    "time": "2021-01-04T13:13:03.228844Z",
                    "timeSinceGPSEpoch": null,
                    "rssi": -49,
                    "loRaSNR": 10.75,
                    "channel": 0,
                    "rfChain": 1,
                    "board": 0,
                    "antenna": 0,
                    "location": {
                        "latitude": 0,
                        "longitude": 0,
                        "altitude": 0,
                        "source": "UNKNOWN",
                        "accuracy": 0
                    },
                    "fineTimestampType": "NONE",
                    "context": "+vj/ZQ==",
                    "uplinkID": "czCJdteKRti37FgiZOX9Lw==",
                    "crcStatus": "CRC_OK"
                }
            ],
            "txInfo": {
                "frequency": 868100000,
                "modulation": "LORA",
                "loRaModulationInfo": {
                    "bandwidth": 125,
                    "spreadingFactor": 12,
                    "codeRate": "4/5",
                    "polarizationInversion": false
                }
            }
        },
        "phyPayload": {
            "mhdr": {
                "mType": "ConfirmedDataUp",
                "major": "LoRaWANR1"
            },
            "macPayload": {
                "fhdr": {
                    "devAddr": "01821d8d",
                    "fCtrl": {
                        "adr": true,
                        "adrAckReq": false,
                        "ack": false,
                        "fPending": false,
                        "classB": false
                    },
                    "fCnt": 0,
                    "fOpts": null
                },
                "fPort": 2,
                "frmPayload": [
                    {
                        "bytes": "Lm0aI9IDshmWOmQ="
                    }
                ]
            },
            "mic": "9b9b387a"
        }
    },
    {
        "uplinkMetaData": {
            "rxInfo": [
                {
                    "gatewayID": "MjUxMhQARgA=",
                    "time": "2021-01-04T13:12:57.223488Z",
                    "timeSinceGPSEpoch": null,
                    "rssi": -49,
                    "loRaSNR": 8,
                    "channel": 2,
                    "rfChain": 1,
                    "board": 0,
                    "antenna": 0,
                    "location": {
                        "latitude": 0,
                        "longitude": 0,
                        "altitude": 0,
                        "source": "UNKNOWN",
                        "accuracy": 0
                    },
                    "fineTimestampType": "NONE",
                    "context": "+p1fPQ==",
                    "uplinkID": "BHCiKYz2RhOjW8ZEtCXWrQ==",
                    "crcStatus": "CRC_OK"
                }
            ],
            "txInfo": {
                "frequency": 868500000,
                "modulation": "LORA",
                "loRaModulationInfo": {
                    "bandwidth": 125,
                    "spreadingFactor": 12,
                    "codeRate": "4/5",
                    "polarizationInversion": false
                }
            }
        },
        "phyPayload": {
            "mhdr": {
                "mType": "ConfirmedDataUp",
                "major": "LoRaWANR1"
            },
            "macPayload": {
                "fhdr": {
                    "devAddr": "01821d8d",
                    "fCtrl": {
                        "adr": true,
                        "adrAckReq": false,
                        "ack": false,
                        "fPending": false,
                        "classB": false
                    },
                    "fCnt": 0,
                    "fOpts": null
                },
                "fPort": 2,
                "frmPayload": [
                    {
                        "bytes": "Lm0aI9IDshmWOmQ="
                    }
                ]
            },
            "mic": "9b9b387a"
        }
    }
]

As mentioned, the next frame was properly confirmed:

***** UpLinkCounter= 1 *****
TX on freq 868.300 MHz at DR 0
txDone
RX on freq 868.300 MHz at DR 0
rxDone(ACK)
Rssi= -54

ChirpStack Frames:

[
    {
        "downlinkMetaData": {
            "gatewayID": "3235313214004600",
            "txInfo": {
                "frequency": 868300000,
                "power": 14,
                "modulation": "LORA",
                "loRaModulationInfo": {
                    "bandwidth": 125,
                    "spreadingFactor": 12,
                    "codeRate": "4/5",
                    "polarizationInversion": true
                },
                "board": 0,
                "antenna": 0,
                "timing": "DELAY",
                "delayTimingInfo": {
                    "delay": "1s"
                },
                "context": "ALBbTQ=="
            }
        },
        "phyPayload": {
            "mhdr": {
                "mType": "UnconfirmedDataDown",
                "major": "LoRaWANR1"
            },
            "macPayload": {
                "fhdr": {
                    "devAddr": "01821d8d",
                    "fCtrl": {
                        "adr": true,
                        "adrAckReq": false,
                        "ack": true,
                        "fPending": false,
                        "classB": false
                    },
                    "fCnt": 691,
                    "fOpts": null
                },
                "fPort": null,
                "frmPayload": null
            },
            "mic": "4f446ed0"
        }
    },
    {
        "uplinkMetaData": {
            "rxInfo": [
                {
                    "gatewayID": "MjUxMhQARgA=",
                    "time": "2021-01-04T13:14:39.130628Z",
                    "timeSinceGPSEpoch": null,
                    "rssi": -43,
                    "loRaSNR": 9,
                    "channel": 1,
                    "rfChain": 1,
                    "board": 0,
                    "antenna": 0,
                    "location": {
                        "latitude": 0,
                        "longitude": 0,
                        "altitude": 0,
                        "source": "UNKNOWN",
                        "accuracy": 0
                    },
                    "fineTimestampType": "NONE",
                    "context": "ALBbTQ==",
                    "uplinkID": "hpHUDxV7Qfe3ialuhKSrxQ==",
                    "crcStatus": "CRC_OK"
                }
            ],
            "txInfo": {
                "frequency": 868300000,
                "modulation": "LORA",
                "loRaModulationInfo": {
                    "bandwidth": 125,
                    "spreadingFactor": 12,
                    "codeRate": "4/5",
                    "polarizationInversion": false
                }
            }
        },
        "phyPayload": {
            "mhdr": {
                "mType": "ConfirmedDataUp",
                "major": "LoRaWANR1"
            },
            "macPayload": {
                "fhdr": {
                    "devAddr": "01821d8d",
                    "fCtrl": {
                        "adr": true,
                        "adrAckReq": false,
                        "ack": false,
                        "fPending": false,
                        "classB": false
                    },
                    "fCnt": 1,
                    "fOpts": null
                },
                "fPort": 2,
                "frmPayload": [
                    {
                        "bytes": "hNrPhBWGjHasU84="
                    }
                ]
            },
            "mic": "c7f1e57c"
        }
    }
]

Hello @mitarbeiter,

One question about this, does it happen only UpLinkCounter= 0 with you reset the device in or happens also later?

Regards.

Thank you for the reply.

As I do not understand the cause of this misbehavior, I could not yet reproduce it. It happens sometimes, independent of the frame counter.

A good explanation would be the LoRa duty cycle. But since the next Frame was confirmed properly a few seconds after, I think we can safely assume that is not it.