checked back on the forum. One advised deauthorising your computer - I opened ADE then hit control/shift and d and the screen will come up to deauthorise. Deauthorised then reauthorised the computer and it worked. Good luck with yours!
This worked for me! Thank you so much!!!
MAKE sure you are in library view [where you can see all the books listed]
Press "ctrl+shift+d" for Windows or "Cmd+shift+d" for Mac
Deauthorization dialog will come up.
once ADE is deauthorized,
Now again AUTHORIZE ADE
Help-> authorize computer.
Hope this works !!