NB-IoT Sim card stopped working

[Thomas Chapelle]

Hi,

we are working on a test program with a thinghy:91 board based on the example "asset_tracker_v2" and we are having issues with some SIM Cards.

We are using iBasis eSimc provided by Nordic and they worked fine so far, we were able to send data with NB-IoT and/or LTE-M.

Then the NB-IoT stopped working and only LTE-M is now possible with those SIM.

We verified the NB-IoT cover with other SIM card, we tried other tester/program and also checked the data remaining on the SIM.

Please, can you give hints on :

- what root cause can explain this behavior ?

- how can we make sure a SIM card is NB-IoT ready ? With which specific AT-CMD ?

Best regards,

[Øyvind]

Hello, 
Do you have any logs that you can provide us?  How do you know it is not working? Do you get any errors? Did you test with other SIM cards?

Kind regards,
Øyvind

[Øyvind]

What modem FW are you running on your device? 

[Thomas Chapelle]

Hi, 

we are using the modem firmware mfw_nrf9160_1.3.7 and the example is based on ncs v2.7.0.

As i said, "We verified the NB-IoT cover with other SIM card".

with another example, serial_lte_modem, we have an ERROR response on XCONNECT but only with this SIM card.

I will try to retrieve some logs.