membership podcasts not downloading

I subscribe to a members only podcast. The Apple podcast app on iPhone mobile has recently been not allowing me to type in the membership information. It downloads the podcast, and then says "this podcast is currently unavailable". It used to pop up with the username/password option, but no longer does. The podcast author has said that he has heard that other's are having the same issue. I hope Apple is working on a fix? Anyone else have a suggestion?