No idea what OS You're running - but on my OSX', I had to deselect WD, save, then re-select WD using the Admin-Browser. Afterwards WD was available.
(happened on all installations here)
Im using Windows. Tried turning the server on and off as well as WD but no luck.
I'm having the same problem.
EDIT: got it working - couple of restarts of the server / IIS and seems to be up and running again.