sftp chroot does'nt pass the login

[Jean-Francois]

Hi,

I am using sftp server with a chroot with following lines in sshd configuration 
file. The same works for my actual server in 4.4 OpenBSD but I just freshly 
installed a 4.7 one and on it the sftp login fails (it works without chroot).

Match group web
        ChrootDirectory /var/www/htdocs
        ForceCommand internal-sftp

Any idea what I get wrong ?

Thanks