Download error on Files app

cannot get any file stored on my iCloud drive to download in the Files app on iOS.

When I tap on a file, either it says instantly Download error, or it stays indefinitely in a Downloading state, without reporting any progress. My iCloud drive is working fine on my Macs. The list of files and directories in Files on iOS is synchronized properly to reflect the changes made on my Mac. It's «only» that I can't download any file.

Had the issue on iOS 11, same on iOS 12.

Tried to delete and reinstall the app, same problem.

Other drives (dropbox) linked to the Files app work perfectly.

Am I the only one with this issue ?

It says : Make sure that you have an active Internet connection on your Mac and on your iPhone, iPad, and iPod touch

Is that the point of iCloud drive? I can't acess my files unless my Mac is connected to the internet?