I've recently bought a SIM900A A6 GSM module. Whenever I send a command it gives an error: +CME error 58.

Does anybody know what this means and how to solve it?

  • Post your schematic and a complete test sketch that show your problem.
    – user31481
    Sep 1, 2017 at 16:44
  • I am also working on A6 and receiving the same error. I suspect it has something to do with the power supply. Will post my final answer once I have finished. Hassan ([email protected]) Oct 6, 2017 at 6:40
  • Which commands are you sending? From my experience it seems the command isn't supported. What happens if you issue just AT or ATZ?
    – Petr
    Oct 28, 2017 at 14:26

2 Answers 2


Your sim card is probably protected by a PIN. Easiest way to get it working is to put the SIM into a normal phone and remove the PIN protection.

  • I've already done that it is receiving text messages and calls but its still giving this error
    – luukito
    Sep 1, 2017 at 20:56

I had the same error. My error was using the incorrect baud rate. Set the baud rate to 115200. Also, ensure that "Both NL & CR" option is selected for new line options. After changing those settings, I had to reboot the A7, and wait for all the status messages to complete before I could send the AT command.

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