Currently, there are some issues where you won't get any new words if you exhaust your review queue and you don't have any lists set to "adding". (HSK Level 1 characters doesn't count, as it's been destroyed).
Skritter should be telling you that you don't have any lists selected, or if you have paused lists, it should be giving you recently reviewed items (although the choosing of those isn't very good right now due to another issue, so they may repeat quickly). There seems to be a bug with that, so it's just not saying anything. Try adding/enabling a list from the vocab lists page.
Also, whiteto2, if you're reading this, you didn't give us a valid email address so I can't respond to your feedbacks -- might this have been the problem you were experiencing?