I had the same problem as you, part of me thinks it has something to do with having an NBA account already. Did you have the preview last year? I did and this year it took me forever to finally get the stuff to launch. It just kept directing me to the place where to buy it. I can't remember exactly how I got it to finally work (making this a useless post), but it is possible, so just keep clicking around, preferably not during a game you're actually interested in. Good luck, wish I remembered what I did. I do think a pop-up finally came up which was the sign that I had to re-enter my email and then the league pass started.