Hello all, anyone have issues with their Xbee 3 LTE-M/NB-IoT modems failing in the field? I have a few running L0.0.00.00.05.11,A.02.16 and Digi firmware 11417 that have stopped transmitting in the field. Upon checking the modem with an XBIB-CU-TH board, all cellular-related data is blank whereas before it was all there. Checked the SIM in another known, working modem and it's fine. When issuing a AT+CGSN results in "ERROR" along with all the other cellular network-related commands.
Also it is known that the modem can get in to an error state if a "Safe shutdown" isn't initiated prior to pulling power. I am using this modem in micropython mode and am issuing an "Airplane Mode" before shutting the modem down. Would like to know why this is happening and how to go about troubleshooting the issue if it only occurs every couple of months...