First of all, Please don't try to open the book w/o Authorization (if you don't know what does it mean).
If you use this option, you will not be able to open the book on any device.
Back to your query,
Did you try to deauthorize (Ctrl+Shift+D) and then Authorize again (help -> Authorize Computer) and then try to open the "acsm" file?
Yes, I tried to deauthorize in Library view, but nothing happened. ADE has no authorization information at all.
So, for added measure, I uninstalled & reinstalled ADE 3.0. Then I confirmed that Adobe ID and password worked by logging into my Adobe account. Hence, my internet connection also works.
In ADE I again entered my Adobe ID and password. Initially I got the same error: cannot connect to authorization server.
After I repeatedly hit [Try Again], the screen finally showed "Authorizing..."
However, this screen just runs...and runs. The authorization never completetes.
So then I went to the Registry and deleted the Adept Key, as you suggested in your other reply.
Same result. At first, it wouldn't connect to the server at all. Then I get the "Authorizing" screen that runs indefinitely.
Has anyone found an answer to this? My computer is doing the same thing!