After having solved the issue regarding 3-in-1 SIM cards described here we replaced all SIM cards and got all devices up and running for approximately a month. Afterwards some of the devices started to fail again, but now we have a
LE_SIM_STATE_UNKNOWN status when checking
cm sim status. Running
AT+CCID returned an error.
Again, there is no way to reproduce the error in our office…
I will check a sensor next Tuesday (3rd of December) and would like to know if any of you guys have some idea and how I could check what the issue is (I do not have a lot of experience with AT commands)?
Thanks in advance