Problems with the "play mow" button.

So, whenever I click the "play now" button to download the game, it directs me to the website https://signup.na.leagueoflegends.com/en. But it doesn't have any content on the page. the rest of the website works until I click that button. I just bought a new computer with windows 8.1 just in case that means anything. what can I do to fix this?