Su - Root Su: Incorrect Password

when log in via user in wheel group it works

but when su to root
it show incorrect password

/etc/pam.d/su

Code:
#%PAM-1.0
auth sufficient /lib/security/$ISA/pam_rootok.so
# Uncomment the following line to implicitly trust users in the "wheel" group.
#auth sufficient /lib/security/$ISA/pam_wheel.so trust use_uid
# Uncomment the following line to require a user to be in the "wheel" group.
#auth required /lib/security/$ISA/pam_wheel.so use_uid
auth required /lib/security/$ISA/pam_stack.so service=system-auth
account required /lib/security/$ISA/pam_stack.so service=system-auth
password required /lib/security/$ISA/pam_stack.so service=system-auth
# pam_selinux.so close must be first session rule
session required /lib/security/$ISA/pam_selinux.so close
session required /lib/security/$ISA/pam_stack.so service=system-auth
# pam_selinux.so open and pam_xauth must be last two session rules
session required /lib/security/$ISA/pam_selinux.so open
session optional /lib/security/$ISA/pam_xauth.so
id

Code:
uid=32006(admin) gid=32010(admin) groups=10(wheel),32010(admin)