adding user to samba failed with smbpasswd

[The Shell <samwun@hgcbroadband.com>]

Just tried to add a user to samba by authenticate wtih the ldap server 
(openldap 2.2.11), but it failed with the error:
Failed to issue the StartTLS instruction: Connect error
The smb.conf file has the corresponding lines as below:
 ldap delete dn = no
 ldap ssl = start_tls
 ldap port = 389

The message display from smbpasswd command is shown below:

root@fbsd [5:01pm] [...samba/lib]# ../bin/smbpasswd -D5 -a root
Netbios name list:-
my_netbios_names[0]="DJR-SAMBA-TEST"
Trying to load: ldapsam:ldap://kerberos.rock.com
Attempting to register passdb backend ldapsam
Successfully added passdb backend 'ldapsam'
Attempting to register passdb backend ldapsam_compat
Successfully added passdb backend 'ldapsam_compat'
Attempting to register passdb backend smbpasswd
Successfully added passdb backend 'smbpasswd'
Attempting to register passdb backend tdbsam
Successfully added passdb backend 'tdbsam'
Attempting to register passdb backend guest
Successfully added passdb backend 'guest'
Attempting to find an passdb backend to match 
ldapsam:ldap://kerberos.rock.com (ldapsam)
Found pdb backend ldapsam
Searching for:[(&(objectClass=sambaDomain)(sambaDomainName=TECH21))]
smbldap_search: base => [dc=kerberos,dc=rock,dc=com], filter => 
[(&(objectClass=sambaDomain)(sambaDomainName=TECH21))], scope => [2]
Failed to issue the StartTLS instruction: Connect error            
<<========== HERE CAUSED PROBLEM.
Connection to LDAP Server failed for the 1 try!
smbldap_search_suffix: Problem during the LDAP search:  (Connect error)
Problem during LDAPsearch: Connect error
Query was: dc=kerberos,dc=rock,dc=com, 
(&(objectClass=sambaDomain)(sambaDomainName=TECH21))
pdb_init_ldapsam: WARNING: Could not get domain info, nor add one to the 
domain
pdb_init_ldapsam: Continuing on regardless, will be unable to allocate 
new users/groups, and will risk BDCs having inconsistant SIDs
pdb backend ldapsam:ldap://kerberos.rock.com has a valid init
Attempting to find an passdb backend to match guest (guest)
Found pdb backend guest
pdb backend guest has a valid init
New SMB password:
smbldap_search: base => [dc=kerberos,dc=rock,dc=com], filter => 
[(&(uid=root)(objectclass=sambaSamAccount))], scope => [2]
Sleeping for 0 milliseconds before reconnecting
Sleeping for 792 milliseconds before reconnecting
Sleeping for 840 milliseconds before reconnecting
Sleeping for 1840 milliseconds before reconnecting
Sleeping for 1944 milliseconds before reconnecting
Sleeping for 9180 milliseconds before reconnecting
Failed to issue the StartTLS instruction: Connect error
Connection to LDAP Server failed for the 7 try!
...