MKR WAN 1310 "Connection to the network failed"

[anon46200358]

I've been unable to get my https://docs.arduino.cc/arduino-cloud/hardware/lora/ tutorial sketch to connect to my Arduino Cloud Thing. I have a Browan gateway setup with my TTN account, conr2286, and I can see received uplink messages (GatewayData.png) from my 1310. The EUIs in the JoinEUI seem to match those in the TTN application (app.png) that the Arduino Cloud created using my Arduino TTN account, conr2286-dc (yes, I have two TTN accounts now). The serial console output (SerialConsole.png) reports the failure (I have LORA_DEBUG directed to Serial and DebugMessageLevel at 4). The forum won't allow newbies to attach my source code (limit of 3 attachments), so where is a good place to begin debugging this?

[anon46200358]

Does anyone see something obviously wrong in my uplinked Join-Request message (pasted below) recorded by the Gateway Server for my gateway. The join_eui (35B0134106B86BCE) really is that of my application, and the dev_eui (A8610A34362D7B16) really is that of my device.

Unfortunately, when I examine the application on TTN, the "Last activity" is "never" apparently suggesting that the Gateway Server didn't forward the Join-Request to Arduino Cloud Network Server (arduino.nam1.cloud.thethings.industries). The Gateway Server is not recording any downlink traffic. And, the executing sketch on my MKRWAN1310 reports "Connection to the network failed."

I've tried the usual smoke and mirrors (moved the gateway 30m away from device, deleted and reconstructed everything, confirmed the app keys match, confirm MKRWAN 1.1.0 version, etc) and laced MKRWAN.h with debug code to confirm the sketch really is passing the expected values to the modem. I am absolutely "stumped," and don't know how to proceed!

Here's the Join-Request uplink message recorded by my Gateway Server:

{
  "name": "gs.up.receive",
  "time": "2024-07-23T23:43:13.438921415Z",
  "identifiers": [
    {
      "gateway_ids": {
        "gateway_id": "eui-5813d3fffe1b35f6",
        "eui": "5813D3FFFE1B35F6"
      }
    }
  ],
  "data": {
    "@type": "type.googleapis.com/ttn.lorawan.v3.GatewayUplinkMessage",
    "message": {
      "raw_payload": "AM5ruAZBE7A1FnstNjQKYai/uuzwkx8=",
      "payload": {
        "m_hdr": {},
        "mic": "7PCTHw==",
        "join_request_payload": {
          "join_eui": "35B0134106B86BCE",
          "dev_eui": "A8610A34362D7B16",
          "dev_nonce": "BABF"
        }
      },
      "settings": {
        "data_rate": {
          "lora": {
            "bandwidth": 500000,
            "spreading_factor": 8,
            "coding_rate": "4/5"
          }
        },
        "frequency": "904600000",
        "timestamp": 1580933726,
        "time": "2024-07-23T23:43:13.340476989Z"
      },
      "rx_metadata": [
        {
          "gateway_ids": {
            "gateway_id": "eui-5813d3fffe1b35f6",
            "eui": "5813D3FFFE1B35F6"
          },
          "time": "2024-07-23T23:43:13.340476989Z",
          "timestamp": 1580933726,
          "rssi": -71,
          "channel_rssi": -71,
          "snr": 10.5,
          "location": {
            "latitude": 45.9170762254361,
            "longitude": -116.063332875997,
            "altitude": 1036,
            "source": "SOURCE_REGISTRY"
          },
          "uplink_token": "CiIKIAoUZXVpLTU4MTNkM2ZmZmUxYjM1ZjYSCFgT0//+GzX2EN7E7PEFGgwIkYCBtQYQ8pud0QEgsP74t4HsFQ==",
          "received_at": "2024-07-23T23:43:13.413179789Z"
        }
      ],
      "received_at": "2024-07-23T23:43:13.438783474Z",
      "correlation_ids": [
        "gs:uplink:01J3GZMH0Y4SNWRR75GWZ5FXZD"
      ]
    },
    "band_id": "US_902_928"
  },
  "correlation_ids": [
    "gs:uplink:01J3GZMH0Y4SNWRR75GWZ5FXZD"
  ],
  "origin": "ip-10-22-13-163.us-west-1.compute.internal",
  "context": {
    "tenant-id": "ChNtaWxsLWNyZWVrLXJlc2VhcmNo"
  },
  "visibility": {
    "rights": [
      "RIGHT_GATEWAY_TRAFFIC_READ"
    ]
  },
  "unique_id": "01J3GZMH0YARXRZETFS13BZ2F2"
}