Which operating system do you use?
I just tried to authorize a new Digital edition installation on windows 10, and get
"Connection error", "Cannot connect to activation server, check internet connection".
So maybe there are problems on adobe server?
Check if your Security Program blocked Digital Edition. Also check if your system used the right time, date and timezone.
You can deauthorise your current ID by pressing Ctrl + Shift + D after opening the ADE.
For those facing connection to the activation server issues, read the following:
This problem occurs with ADE 4.5 version.
What you can do is to download and install ADE 3.0, the link is here: Download | Adobe Digital Editions Home
Make sure that you have install both version 3 and 4.5
Open version 3 and authorise with your Adobe ID. It should be able to overcome the activation server issues.
Open a ebook with it and then close ADE 3 and uninstall the software.
Open ADE 4.5 and you will see the ebook in it, and the software is already authorised by itself.
But you will not be able to download and open subsequent ebook under ADE 4.5, unless you follow the below instructions.
Now the trick is to make sure that when you download the next ebook, associate it with ADE 4.5 (because by default, the computer will
use ADE 3 to open it. You can associate it from the program folder, under Adobe/ADE 4.5, look for the AdobeEditions.exe file.
Subsequently, there is no need to associate it anymore.