Can't redeem iTunes gift card! Anyone have an answer??

Just got an iTunes card as a gift; I tried to redeem it and an error keeps popping up saying "the card hasn't been properly activated." Could someone explain what this means and how I can correct the issue??! I've tried to sign in & out, caps & lower case letters, etc. and nothing seems to work!! I'm getting super irritated at this point so any help would be appreciated!!! Thanks!!