Samba 4.0.5 empty guest password

["Géza, Gémes"]

Hi,

For some reasons I need to enable the guest account in our two samba 
4.0.5 DCs controlled AD domain.
I've set:
#samba-tool domain passwordsettings show
Password informations for domain 'DC=kzsdabas,DC=hu'

Password complexity: off
Store plaintext passwords: off
Password history length: 0
Minimum password length: 0
Minimum password age (days): 0
Maximum password age (days): 365

I've set an an empty password for the guest account via ADUC.

When I try to connect to the sysvol share with:
smbclient //dc0/sysvol -U guest%''
I get:
Anonymous login successful
Domain=[KZSDABAS] OS=[Unix] Server=[Samba 4.0.5]
tree connect failed: NT_STATUS_ACCESS_DENIED

Thank you for any idea!

Cheers

Geza Gemes