i have a linode and i access via ssh throw terminal. I need to create an sftp user which his default directory (and the only he can acces) is /var/www/xxxxxx.com/public_html/directory

Now, i did it, but when i try to connect i get broken pipe or connection rejected by peer

what i did is this:

$ adduser --home /var/www/xxxxxx.com/public_html/directory/ username
$ chown username:username /var/www/xxxxxx.com/public_html/directory/
$ chmod 755 /var/www/xxxxxx.com/public_html/directory/
$ nano /etc/ssh/sshd_config

In /etc/ssh/sshd_config add following lines

Match User username
   ChrootDirectory /var/www/xxxxxx.com/public_html/directory/
   AllowTCPForwarding no
   X11Forwarding no
   ForceCommand internal-sftp

What im doing wrong?

If you're jailing the user to '/var/www/xxxxxx.com/public_html/directory/', then that directory needs to be owned by root, not the user. Anything in the directory can be owned by the user however.