GM862 - AT command cpin OK but Timeout anyway

Hi

I have a problem with the AT command cpin.

when i send AT+cpin=1234 it replies with “ok” but after 20 seconds sharp the GM862 turns the power off.

I tried searching the manual and web for anwsers, but unfortunately no succes. What i did find in the manual was a time-out of 20sec for cpin errors.

Also the remarks about the power supply i took notice of, i’m using a 12V 5A external powere supply.

Can anyone shine a light on this problem?

Thank you very much in advance.