itunes radio quits after one song on imac

I have experienced problems with iTunes Radio from the start. It usually seems to play one song and then quit. If I try to reselect the same station, it will not play. If I try a separate station, it will not play. If it did this consistently, I would drop it (and the icloud subscription) for spotify. But sometimes, it seams to work ok- for a few minutes. Just enough to keep me on the hook, I guess.