Suddenly my ADE won't recognize me, my nook, or my library books.

I have been using digital editions for years on my Mac w/my Nook.  Today, I plugged in my nook to load on some new library books and the books won't open.   I get the following error message: "Error getting License. License Server Communication Problem:E_ACT_NOT_READY."   This keeps happening.  I restart the computer.  I restart my nook.  I uninstall and reinstall ADE.  Finally, I try unauthorizing it and get the following error message: "Unable to erase authorization.  Please try after some time."  Well, I've been trying.  Nothing.  Any advice?