E_AUTH_NOT_READY

For this problem, you need to deauthorize and authorize ADE again.

Launch ADE

Help -> Erase authorization.

ADE will be deauhorized.

If due to some reason, you are unable to deauthorize ADE, follow the below steps:

Mac:

1. Go-> Go to folder.

Go to folder dialog will appear.

2. Type   ~/Library/Application Support/Adobe/Digital Editions

drag the activation.dat file to the trash.

ADE will be deauthorized now.

Now Authorize ADE again [Help -> Authorize Computer].

Windows:

Choose Start > Run.

In the Open text box, type regedit and then press Enter. The Registry Editor opens.

In the left pane of the Registry Editor, locate the following registry key:

HKEY_CURRENT_USER\Software\Adobe\Adept

Right-click the Adept key and choose Delete.

In the Confirm Key Delete dialog, click OK.

Your authorization will be deleted.

ADE will be deauthorized now.

Now Authorize ADE again.

I am also receiving this message. I cannot authorize my computer or access my ebook for an important class or download it onto another computer.