samba - Jun 2017 - smbpasswd against DC with different netbios name

I have an Active Directory w2k12r2, and I'm trying to change domain user
passwords with smbpasswd from, Linux clients, but I get "Failed to change
password" error. I guess the problem arise because I promoted my AD with a
different netbios name, I mean: my domain is xet.test.cu and my netbios name is
INET (instead XET, by default)
I've promoted another AD with netbios name XET (settled by default), and
smbpasswd works well. BUT in my server with a different netbios name (INET)
works this: smbpasswd -r <ip_domain_controller> -U user1, but do not works
with domain name: smbpasswd -r xet.test.cu -U user1

Any idea? Could this be a bug? 

_________________________________________ 
Ing. Felipe_ González_Santiago 

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