in smb.conf
passdb backend = ldapsam:ldaps://ldapserver
ldap suffix = o=zzz
ldap ssl = on
ldap admin dn = uid=xxx,ou=yyy,o=zzz
(set secret for admin dn with smbpasswd -w)

# smbclient -L //machine
read_socket_with_timeout: timeout read. read error = Connection reset by peer.
protocol negotiation failed

it doesnt prompt for password yet does initial authentication with ldap admin dn
to ldap server..ldap logs show results ok with no errors
: BIND dn="uid=xxx,ou=yyy,o=zzz" method=128
: BIND dn="uid=xxx,ou=yyy,o=zzz" mech=simple ssf=0
: RESULT tag=97 err=0 text=
: SRCH base="o=zzz" scope=2
filter="(&(objectClass=sambaDomain)(sambaDomainName=MYDOMAIN))"
: SRCH attr=sambaDomainName sambaNextRid sambaNextUserRid sambaNextGroupRid
sambaSID sambaAlgorithmicRidBase objectClass
: SEARCH RESULT tag=101 err=0 nentries=1 text=
: closed


if smb.conf has
ldap suffix = dc=somesearchbase
(or if not set)

# smbclient -L //machine
password: 

but will fail because ldap server setup uses o= in dn 
: BIND dn="uid=xxx,ou=yyy,o=zzz" method=128
: BIND dn="uid=xxx,ou=yyy,o=zzz" mech=simple ssf=0
: RESULT tag=97 err=0 text=
: SRCH base="" scope=2
filter="(&(objectClass=sambaDomain)(sambaDomainName=MYDOMAIN))"
: SRCH attr=sambaDomainName sambaNextRid sambaNextUserRid sambaNextGroupRid
sambaSID sambaAlgorithmicRidBase objectClass
: RESULT tag=101 err=32 text=
: SRCH base="" scope=2 filter="(&(uid=myuserid)(objectClass=sambaSamAccount))"
: SRCH attr=uid uidNumber gidNumber homeDirectory sambaPwdLastSet
sambaPwdCanChange sambaPwdMustChange sambaLogonTime sambaLogoffTime
sambaKickoffTime cn displayName sambaHomeDrive sambaHomePath sambaLogonScript
sambaProfilePath description sambaUserWorkstations sambaSID sambaPrimaryGroupSID
sambaLMPassword sambaNTPassword sambaDomainName objectClass sambaAcctFlags
sambaMungedDial
: RESULT tag=101 err=32 text=
: closed