I have a problem unlocking the SIM card using my most recent Fona modules. I have formerly done two other projects based on these and I never had a problem unlocking the SIM card. What is teh most interesting is that the function returns immediately. There is no delay as it usually is when unlocking a SIM. Any suggestions as to what may cause this?
Here's the output (with debug) that I get when running the FonaTest sketch.
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FONA> n
---> AT+CREG?
<--- +CREG: 0,0
Network status 0: Not registered
FONA> U
Enter 4-digit PIN
1234
Unlocking SIM card: ***AT+CPIN=1234
***
---> AT+CPIN=1234
<--- ERROR
Failed
The FM radio and reading info from the FONA works fine, but it|s impossible to unlock the SIM :(