XB3-C-GM1-UT-001 module in UK stops attempting to register to network prematurely?

XBee & XBee Gateway
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1

We are experience a variability attempting to connect to Vodafone’s NB-IoT network from module to module. Our device profile has a confirmed functional APN, Bandmask, Carrier Profile settings, and destination address (with whitelisting).

Most of our module and SIM cards function without issue once configured. However some never succeed in registering to the network.
When observing the AI indicator, the status oscillates between initializing (0xFF) for ~10s and registering (0x22) for ~2 seconds. The failed units never proceed to connecting to the internet (0x23) or joined (0x00). They also do not indicate a rejected registration (0x25); the RJ cause indicator remains 0.

ICCID number is correctly displayed in the settings page, I assume there is no issue with the module reading the SIM card. No activity was registered on the portal.

USB power supply, and antennas used for testing were common with the functional units.

This issue was observed in RevD hardware versions.

2

Try issuing an ATAN with the APN, ATWR, ATNR.

Try the SIM is a different module to see if the issue follows the SIM or the module.

Make sure that you are running the most current version of the firmware on the radio.

Make sure that the SIM is active and set to allow access to the CATM/NBiOT network.