Download will not complete

I am trying to download a library book from a university library.  I have tried this before, but in every case the download stops about 25% of the way in.  It just sits there, will not complete.  It's not the internet, because I've been using that all day and have had no problems.  I'm using a MacBookPro with OS 10.10.5.  I don't know what version of Digital Editions I'm running, because the fool program does not have an "about" window!