sim not valid

Hello i just got a new iphone, when im trying to activate it, it shows this message

"Sim Not Valid"

The sim card that you currently have installen in this Iphone is from a carrier that is not supported under the activation policy tha is currently assigned by the activation server,

this is not a hardware issue with the Iphone,Please insert another Sim Card from a supported carrier ore request this iphone be unlocked by your carrier,Please contact appple for more information,