The issue shown in your screenshot may have been a temporary issue with our servers. Are you still getting this error message?
For the Plug-ins do make sure that you have redeemed the CC4 versions from your Reallusion Account > Registration page. Once you do that you should be able to install them using the Reallusion Hub. However, if you have already installed trial versions, please uninstall those first and then install the full versions with CC4 closed down.
Peter
Forum Administrator
www.reallusion.com