Can't change privilege for a user

Hi All,
I have created a new user and can change the users privilege via the gui.
If I try the same thing via the command line I receive the following error: that’s not a valid privilege ().
The command I used:
sudo curl -X POST -d "email=test@abc.example.org" --user admin@example.org:password https://box.example.org/admin/mail/users/privileges/remove

Any idea’s?

Thanx

Julian