I use digital editions to read books from my public library. Suddenly when it was downloading a borrowed book it gave my an error as follows: "Connection error detected - Digital Editions could not connect to the fulfillment server. Please make sure you are connected to the Internet". The internet is fine so I uninstalled Digital Editions and re-installed it. When I tried to authorize it it gave me the same error as above. I contacted my library who said I should switch my firewall off and try again. Did this and unfortunately it didn't help. Has anyone else had this problem and found a solution?
I started having the same problem this week. ADE had worked fine until now. Like you I started by not being able to connect to the fulfillment server. I tried all the fixes, uninstalled, reinstalled, rebooted, nothing worked, couldn't deauthorize my computer so resorted to the control shift d option, that deauthorized, but then I couldn't authorize my computer, got the error could not connect to the activation server. I went through all the uninstalling, reinstalling several times, and was getting very frustrated. Finally I went into my admin account, ADE showed authorized there, tried to add a borrowed library book & it told me that I had to authorize, so I clicked on help, deauthorized, then authorized, the book transferred, plugged in my Kobo Glo & added the book to it. When I logged off of my admin account & went back to the account I normally use, my ADE still shows that it isn't authorized & the book I added is not in my library. So I guess I have to use it from my admin account on my computer. It is kind of annoying, but at least I found a fix that actually worked for me.