Downloaded Adobe Digital Editions: Won't let me authorize; tells me I have a connection problem. However, I can access the internet with no problem.

I downloaded Adobe Digital Edition 4.0.2 on two computers.  I downloaded a book onto one.  On the second computer, I tried to download, it asked me for my Adobe ID and Password, then said I had a connection problem.  I don't believe I have one to the extent I can access the internet.  Help appreciated.  Thanks!