can't chroot new users

On my Apache server I need to create new user accounts that would only access a specific folder, but when I try to change their root directory in ssh the server refuses to do it. I tried to edit the sshd_config file to change the root directory of every accounts automatically. Here is the code:

Match Group sftpusers
ChrootDirectory /var/www/clubs/%u
ForceCommand internal-sftp
X11Forwarding no
AllowTcpForwarding no

the idea is to set the root directory of user1 to /var/www/clubs/user1 if he belongs to the sftpusers group.

The server refuses the connection and according to the logs the user was trying to access "/".

Please let me know if you need more informations.