When the NB-IoT module and real NB-IoT network are used to access the IoT platform, the first step is to bind a device.

If the device fails to be bound, you can troubleshoot the error by checking the following items:

• When you register the device on the platform, are the values of nodeId and verifyCode correct? Is the timeout period too short?

  The values of nodeId and verifyCode must be the IMEI of the NB-IoT module. In addition, the timeout period should be long enough, so that the device can send a binding request to the platform within the period after the registration is successful.

• Is the product information used during device registration the same as that in the product model?

  If you register the device in the IoTDA console, ensure that the correct product model is selected. If you call an API to register the device, make sure the value of deviceInfo is the same as that defined in the profile.

• Is the signal from an NB-IoT base station reaching the module?

  Run the AT+CSQ? command to check the NB-IoT signal strength. If there is no signal or the signal strength is weak, contact the carrier.

• Can the NB-IoT module be attached to the network?

  Run the AT+CEREG? command to obtain the network registration details. If the returned status is unregistered or rejected, contact the carrier. The version of the NB-IoT module may not match the version of the carrier's base station.

• Can the NB-IoT module ping the HUAWEI CLOUD IoT platform?

  Run the AT+NPING command to ping the HUAWEI CLOUD IoT platform. If the platform cannot be pinged, it indicates that the carrier's network cannot reach the public network. Contact the carrier to check if its core network is connected to the public network and if the core network can be connected to only the carrier's IoT platform. Work with the carrier on the connection to the public network.

• Are the domain name and port of the platform correctly set for the NB-IoT module?

  Run the AT+NCDP command to set the domain name and port of the platform. To obtain the domain name and port, log in to the IoTDA console and check the connection details of CoAP or CoAPs devices.

• Does the AT command sent to the NB-IoT module end with \r\n?

  Each command sent to the NB-IoT module must end with \r\n. If not so, the command is cached in the NB-IoT module.

• Is the transmitted data in the "SENT" status in the NB-IoT module?

  Run the AT+NQMGS command to check the status of the commands sent.

  PENDING: The data was sent but the platform has not responded.

  SENT: The data was sent and the platform has responded.

  ERROR: Data reporting is abnormal.

  If the status is PENDING or ERROR, there may be network issues. Check the base station and core network.

• Can the AT+NMGS data sent by the NB-IoT module be parsed properly?

  Use the codec test tool to check whether the streams to be sent can be parsed.