As we understand it, NewsBlur changed its API which has in turn caused a few headaches. The developer has let us know they are feverishly working on an update that will right the ship. They are hoping to have a fix in place by the end of the week.
We'll keep our fingers crossed that they are successful and if you haven't tried Feed Me, there's a trial version available and the full version will run you $1.99. Feed Me is compatible with Windows Phone 8 and 7.x devices and you can find it here in the Windows Phone Store.