Check if your SIM card is PIN protected. You can disable PIN protection on the SIM card itself or set PIN in PRI configuration tool in menu Basic parameters.

Check if you have correct SIM identification set. You can do that in the menu Gateway configuration > GSM basic parameters > SIM card number. Correct value is IMSI.

Check if you have inserted SIM card to the right SIM holder position.

Try the SIM card in different GSM / UMTS. In case that there works, then the problem is probably hardware oriented.

In case that nothing helps, send us a trace of GSM module reset. To reset the module you have to connect to HyperTerminal, run AT command at&gxx=reset (where xx is number of module), start a trace and let it run for at least 5 minutes.

In case of UMTS network you should check UMTS module band and priority settings. You can set it in Gateway configuration > GSM basic parameters > Use network and Searching priority.

Check the roaming status of SIM card. In case that SIM card is not used in its home network, you can allow connection to another network in Gateway configuration > GSM outgoing groups > Roaming enabled for network and fill the code of presently used network instead of your home network.