Same thing is happening to me. I checked the website here and saw there was now the 2021 version so I updated to that but still get the same message when trying to download the update from Sidekick. I updated through the Comicbase 2021 itself. Then I wanted to do a save to the cloud from Sidekick and it just kept grinding and grinding for soooo long that I just canceled it. Sidekick 2021 doesn't seem to be working.