Are you a U.S. permanent resident or U.S. citizen? It only works for foreigners, I believe, as U.S. residents don't need I-94 forms (the old cardboard slips).

Are you a U.S. permanent resident or U.S. citizen? It only works for foreigners, I believe, as U.S. residents don't need I-94 forms (the old cardboard slips). I'm also not sure if it works for Canadians, as Canadians can also travel to the U.S. more easily.