The phone you have is locked to a carrier, other than the one that you have inserted the SIM for. You need to find out what carrier the device is locked to. You should know that from where you purchased the device. If you do not want to use the carrier the device is locked to, you will need to contact them to see if the offer unlocking services. If they do, see if you qualify. If you do, then follow their instructions for unlocking the device. If you do not qualify, then you will not be able to use the phone. I suggest you return it to where you purchased it for a refund, and purchase a phone you can use with your carrier.