Since Android version 4.2.1, a security feature has been introduced in the Operating System that prevents our SIM cards from switching networks properly. This can prevent the GigSky SIM card from connecting to the correct network.
If you have an Android device running 4.2.1 or later, activate the SIM PIN, found in:
Settings -> Security -> Setup SIM Card Lock -> Lock SIM Card.
You will be prompted for the default SIM PIN, which should be 12345678 for all GigSky SIM cards. NOTE: If your device does not accept 12345678 as the valid PIN code, please contact us either by email at email@example.com, or on +1-650-353-3323, and we will verify the valid PIN code for your GigSky SIM card. If you enter the incorrect PIN code too many times, you will permanently disable your SIM card.
When you have activated the SIM card PIN lock, reboot your device (or power off and on again). You will be prompted for your SIM card PIN code. Enter the code, and then go to the Lock SIM Card menu and de-activate the SIM Card Lock (unless you want to have to enter the SIM card PIN code every time you turn your device on). Don't forget to reboot your device after de-activating the SIM card lock.
Your SIM card will now be able to switch networks properly.