Recently got a Iphone 4s from a friend for my brother.
I went to settings - general - about - where it then told me under carrier was Fido.
I went out and bought a Fido sim card and activated it online, added a $10.00 phone card and inserted the sim card into the phone. It then pops up with a message saying " SIM Card Not Vaild "
How can I fix this problem?
** Edited to remove private information **