Sorry to hear you are having problems downloading your content.
Are you able to download other Marketplace content without problems? If so then it may be an issue with this particular content. If this is the case, please can you let us know the name of the content pack/item that is causing this error message so we can check it.
However, if you are getting this error message with all content downloads, then please contact Technical Support using the link below and they will be able to advise you further.
https://www.reallusion.com/CustomerSupport/UserEx/QForm.html
Peter
Forum Administrator
www.reallusion.com