connect ldap server using php over ssl

connect ldap server using php anonymous is fine.

But , when I try to over ssl using the code below.

<?php
 echo "<h3>LDAP query test</h3>";

 define("LDAP_USERBASE","cn=1019157,ou=students,ou=users,ou=comp,ou=destech,o=rgu");
 $username = "1019157";
 $password = "XXXXXX";
 $ldap = ldap_connect("10.52.1.246",636) or die("Can't connect to LDAP server");
 $user = "uid=" . $username . "," . LDAP_USERBASE;
 echo $user;
 ldap_set_option($ldap, LDAP_OPT_PROTOCOL_VERSION, 3) ;
 if (ldap_bind($ldap, $user, $password)) {
  ldap_unbind($ldap);
  echo 'OK - Login valid';
 } else {
  die(ldap_error($ldap) . ' (' . ldap_errno($ldap) . ')');
 }
 ldap_close($ldap);

?>

it gave the error

Can't contact LDAP server (-1)

someone said that php doesn't support over ssl. really?