this is my first time gifting cards so i'm not sure. when you purchase cards sometimes there's a delay on the new user's ability to use the card. that might be what is happening here.

you'd be able to see this going to your collection and selecting the cards. on the card list screen, there's a status column. if the little clock is highlighted, there's a delay on your ability to use the card. it should only be a few days at most.

it's frustrating that i can't see the status of that card now that it's yours....

now that i think about it more, i think this system is to deter an account from using one card collection for multiple different accounts, as the delay would hinder their ability to abuse the single set of cards.