$conf['auth']['ldap']['binddn'] = '%{user}';
$conf['auth']['ldap']['usertree'] = 'O=Organization';
$conf['auth']['ldap']['grouptree'] = 'RootDSE';
$conf['auth']['ldap']['userfilter'] = '(&(|(CN=%{user})(uid=%{user}))(objectClass=dominoPerson))';
$conf['auth']['ldap']['groupfilter'] = '(&(objectClass=dominoGroup)(member=CN=%{cn}*))';
$conf['auth']['ldap']['referrals'] = '0';
$conf['auth']['ldap']['version'] = '3';
$conf['auth']['ldap']['debug'] = '1';
to
$conf['auth']['ldap']['binddn'] = '%{user}';
$conf['auth']['ldap']['usertree'] = 'O=Organization';
$conf['auth']['ldap']['grouptree'] = '';
$conf['auth']['ldap']['userfilter'] = '(&(|(CN=%{user})(uid=%{user}))(objectClass=dominoPerson))';
$conf['auth']['ldap']['groupfilter'] = '(&(objectClass=dominoGroup)(member=CN=%{cn}*))';
$conf['auth']['ldap']['referrals'] = '0';
$conf['auth']['ldap']['version'] = '3';
$conf['auth']['ldap']['debug'] = '1';
and this
//if ($this->cnf['grouptree'] && $this->cnf['groupfilter']) {
if ($this->cnf['groupfilter']) {
All work fine. What about
RootDSE