It is as simple as the map being down, it may have came back already.
I suggest checking how many people are online, before you restart your computer/delete/re-installing the game.
To check how many people are online, you can hover your mouse over the right side of the website, near the sidebar, and a smaller window will pop out.
(http://i50BannedImageSite/2eyzup2.jpg)
(You'll need to refresh the page to see the current amount.)