samba-common-4.9.3-1.ppc smbd fail to connect to LDAP server

We recently switched from QAS-AD authentication to idsldap-AD authentication. 
Having trouble starting samba with LDAP. 


Error from smbd.log file:
smbldap_search_ext: base => [], filter => [(&(objectClass=sambaDomain)(sambaDomainName=TESTSAC2P))], scope => [2]
[2021/02/16 13:47:29.397489, 5, pid=18612628, effective(0, 0), real(0, 0)] ../source3/lib/smbldap.c:1173(smbldap_close)
The connection to the LDAP server was closed
[2021/02/16 13:47:29.397521, 10, pid=18612628, effective(0, 0), real(0, 0)] ../source3/lib/smbldap.c:648(smb_ldap_setup_conn)
smb_ldap_setup_connection: ldap://ldapserver.mydomain.com
[2021/02/16 13:47:29.418765, 0, pid=18612628, effective(0, 0), real(0, 0)] ../source3/lib/smbldap.c:628(smbldap_start_tls)
Failed to issue the StartTLS instruction: Connect error

Any suggestions on how to configure the smb.conf file for LDAP? 

thanks.