I tried on several devices yesterday to access wd2go.com. I even tried the website below and it confirmed that the site was down.
I then checked the forum to find: http://community.wd.com/t5/WD-My-Cloud-Mobile-Apps/wd2go-com-down/td-p/542647
So clearly the site goes down regularly and so cloud access to your files is not always possible.
Anybody know if this problem is being addressed?