We use the bg96 module in our IOT devices.
Last week we got a returned device from a customer. The device did work a 21 month just fine and then it suddenly stopped connecting.
After investigation, it i did see that the bg96 just does not connect anymore.
E.g.
AT+QGMR
BG96MAR02A08M1G_01.012.01.012
OK
AT+CPIN?
+CPIN: READY
OK
AT+COPS=?
ERROR
The “AT+COPS=?” only takes a few milliseconds.
I have tested the SIM card in another device: it connects just fine.
What could have caused this (to prevent this from happening in other devices)?
And what can be done to fix this?