samba - May 2017 - PDC Domain Samba4+LDAP NTStyle Reject Samba3.x Centos5.

Hi guys.

I migrate our PDC domain running Centos 5+samba3.x+LDAP2.3.x to Centos
7+samba4+ldap2.4.x

I forget we have a domain member running centos 5.11 with samba Version
3.6.6-0.138.el5_10

I test my domain member with centos 6 running samba  Version 3.6.23-42.el6_9

My samba member won't find any domain, I try to remove the account from the
domain and
join back but no luck.

net rpc join -S MYPDC -U root
Unable to find a suitable server for domain MYDOMAIN
Unable to find a suitable server for domain MYDOMAIN

I have to find what parameters need to change, any comments will be
appreciated.

I'm migrating everything to centos7, but forget this guy :-\.

Thanks.

LIving the dream...