iCloud doesn't start syncing after setting up new user

[johannnn]

I just created a user on my SOs computer. I logged in with my iCloud and used all default settings. Everything works great, except that iCloud in Finder doesn't sync anything. iMessages, Photos, Notes, Reminders, Calendar all work great syncing with iCloud. But when I go into Finder, the iCloud Drive folder is empty (except for the empty Desktop and Documents folders).

I've tried going into System Preferences -> Apple ID -> iCloud, and unchecked iCloud Drive, and then checked it. No change..

Dropbox and OneDrive sync fine. But I just don't know how to troubleshoot iCloud Drive.

Any recommendations?