How can I get my iPhone 6S to read my new SIM card?

[iMore Question]

I've been using iphone 6s with a sim card and now I want to change the same sim card ( put a new card ) . I try doing that but the phone doesn't read the sim card but when I change it back to the old sim card it works perfectly . What do I do for the phone to read the new sim card too ?

 

[Just_Me_D]

Re: Switching sim cards in a Iphone 6s

The device is probably locked to a cellular provider.