[Samba] samba group root:"domain users" not found

[marco pirola]

Hi all. I have this question: if put chown root:"Domain User" /patch/ i 
optain error:group not found. This is my parametred.

# Global parameters
[global]
security = ADS
workgroup = ROBINOOD
realm = ROBINOOD.TST
dns forwarder = 192.168.1.6
log file = /var/log/samba/%m.log
log level = 1

# Default ID mapping configuration for local BUILTIN accounts
# and groups on a domain member. The default (*) domain:
# - must not overlap with any domain ID mapping configuration!
# - must use a read-write-enabled back end, such as tdb.
idmap config * : backend = tdb
idmap config * : range = 3000-7999
# - You must set a DOMAIN backend configuration
# idmap config for the SAMDOM domain
idmap config ROBINOOD : backend = rid
idmap config ROBINOOD : range = 10000-999999

while /etc/nsswitch.con is set as for link 
https://wiki.samba.org/index.php/Setting_up_Samba_as_a_Domain_Member