Unable to download Error getting License. License Server Communication Problem: E_ACT_NOT_READY. Cannot open ebooks on my Adobe DE. How do I fix this?

1/1/2023, years after the initial post and we still have the same problem

My solution on a MacBook Pro with El Capitan

1. Opened my hidden Library folder

   a. Opened Finder

   b. Pushed & Held “Option” key and clicked “Go” in the title bar (“Library” appeared)

   c. Clicked “Library” while Holding “Option” key

2. Went to /Application Support/Adobe/Digital Editions

3. Deleted the “activation.dat file”

4. Deleted Adobe Digital Editions (I did it with Clean My Mac 3 but you probably won’t need to use it for the deletion)

5. Emptied Trash

6. Reinstalled Adobe Digital Editions 4.5

7. Adobe Digital Editions opened authorization popup, which I filled out

8. My files now open perfectly

My solution on a MacBook Pro with El Capitan

1. 1. Opened my hidden Library folder

   a. Opened Finder

   b. Pushed & Held “Option” key and clicked “Go” in the title bar (“Library” appeared)

   c. Clicked “Library” while Holding “Option” key

1. 2. Went to /Application Support/Adobe/Digital Editions
2. 3. Deleted the “activation.dat file”
3. 4. Deleted Adobe Digital Editions (I did it with Clean My Mac 3 but you probably won’t need to use it for the deletion)
4. 5. Emptied Trash
5. 6. Reinstalled Adobe Digital Editions 4.5
6. 7. Adobe Digital Editions opened authorization popup, which I filled out
7. 7. My files now open perfectly

I had the exact same problem & this worked for me. All I needed was the first step. Good luck!!!! (copied from another thread):

"Sometimes ADE gets its registration/activation confused and in a semi-authorized state.

Uninstalling and reinstalling does not help, and indeed installation can even trigger this state.

Unfortunately, it often then gives misleading error messages about what is wrong.

A common incorrect message informs you that the ID is already in use on another computer and cannot be reused.

Another is  "E_AUTH_NOT_READY"

This can often be resolved by completely removing any authorization using ctrl-shift-D to the Library screen on ADE (cmd-shift-D if on Mac).

Restart ADE, and then reauthorize with your (old) Adobe ID.

In extreme cases on the mac, the following extra step has helped some people.  Navigate to /Users//Library/Application Support/Adobe/Digital Editions and drag the activation.dat file to the trash. If you are using 10.7, see Access hidden user library files | Mac OS 10.7 Lion. http://forums.adobe.com/thread/1265248?tstart=0