after enable the debug mode , the system shown this error :

PHP notice
Constant LDAP_OPT_DIAGNOSTIC_MESSAGE already defined

/volume1/web/LimeSurvey/application/controllers/admin/tokens.php(1883)

1871
1872 $aData['duplicatelist'] = $duplicatelist;
1873 $aData['invalidemaillist'] = $invalidemaillist;
1874 $aData['invalidemailcount'] = $invalidemailcount;
1875 $aData['resultnum'] = $resultnum;
1876 $aData['xv'] = $xv;
1877 $aData['xy'] = $xy;
1878 $aData['xz'] = $xz;
1879
1880 $this->_renderWrappedTemplate('token', array('ldappost'), $aData);
1881 } else {
1882 $sErrorMessage = ldap_error($ds);
1883 define("LDAP_OPT_DIAGNOSTIC_MESSAGE", 0x0032);
1884 if (ldap_get_option($ds, LDAP_OPT_DIAGNOSTIC_MESSAGE, $extended_error)) {
1885 $sErrorMessage .= ' - '.$extended_error;
1886 }
1887 $aData['sError'] = sprintf(gT("Can't bind to the LDAP directory. Error message: %s"), ldap_error($ds));
1888 $this->_renderWrappedTemplate('token', array('ldapform'), $aData);
1889 }
1890 try {
1891 @ldap_close($ds);
1892 } catch (Exception $e) {
1893 // No handling needed
1894 }
1895
Stack Trace
#0
– /volume1/web/LimeSurvey/application/controllers/admin/tokens.php(1883): define("LDAP_OPT_DIAGNOSTIC_MESSAGE", 50)
1878 $aData['xz'] = $xz;
1879
1880 $this->_renderWrappedTemplate('token', array('ldappost'), $aData);
1881 } else {
1882 $sErrorMessage = ldap_error($ds);
1883 define("LDAP_OPT_DIAGNOSTIC_MESSAGE", 0x0032);
1884 if (ldap_get_option($ds, LDAP_OPT_DIAGNOSTIC_MESSAGE, $extended_error)) {
1885 $sErrorMessage .= ' - '.$extended_error;
1886 }
1887 $aData['sError'] = sprintf(gT("Can't bind to the LDAP directory. Error message: %s"), ldap_error($ds));
1888 $this->_renderWrappedTemplate('token', array('ldapform'), $aData);
#1
unknown(0): tokens->importldap("371646")
#2

• /volume1/web/LimeSurvey/framework/web/actions/CAction.php(109): ReflectionMethod->invokeArgs(tokens, array("371646"))
  #3
  – /volume1/web/LimeSurvey/application/core/Survey_Common_Action.php(83): CAction->runWithParamsInternal(tokens, ReflectionMethod, array("r" => "admin/tokens/sa/importldap/surveyid/371646", "sa" => "importldap", "surveyid" => "371646", "iSurveyId" => "371646", ...))
  78 $oMethod = new ReflectionMethod($this, $sDefault);
  79 }
  80
  81 // We're all good to go, let's execute it
  82 // runWithParamsInternal would automatically get the parameters of the method and populate them as required with the params
  83 return parent::runWithParamsInternal($this, $oMethod, $params);
  84 }
  85
  86 /*
  87 Some functions have different parameters, which are just an alias of the
  88 * usual parameters we're getting in the url. This function just populates
  #4
• /volume1/web/LimeSurvey/framework/web/CController.php(308): Survey_Common_Action->runWithParams(array("r" => "admin/tokens/sa/importldap/surveyid/371646", "sa" => "importldap", "surveyid" => "371646"))
  #5
• /volume1/web/LimeSurvey/framework/web/CController.php(286): CController->runAction(tokens)
  #6
• /volume1/web/LimeSurvey/framework/web/CController.php(265): CController->runActionWithFilters(tokens, array())
  #7
  – /volume1/web/LimeSurvey/application/controllers/AdminController.php(158): CController->run("tokens")
  153 $this->redirect(array('/admin/authentication/sa/login'));
  154 }
  155 }
  156 }
  157
  158 return parent::run($action);
  159 }
  160
  161 /*
  162 Routes all the actions to their respective places
  163 *
  #8
• /volume1/web/LimeSurvey/framework/web/CWebApplication.php(282): AdminController->run("tokens")
  #9
• /volume1/web/LimeSurvey/framework/web/CWebApplication.php(141): CWebApplication->runController("admin/tokens/sa/importldap/surveyid/371646")
  #10
• /volume1/web/LimeSurvey/framework/base/CApplication.php(185): CWebApplication->processRequest()
  #11

• /volume1/web/LimeSurvey/index.php(194): CApplication->run()
  2019-03-22 12:21:37 nginx/1.13.3 Yii Framework/1.1.19

  the below is the LDAP.php setting :

  $serverId = 0;
  $LDAP_server[$serverId] = "l72.16.2.184";
  $LDAP_server[$serverId] = "389";
  $LDAP_server[$serverId] = "ldapv2";
  $LDAP_server[$serverId] = "none";
  $LDAP_server[$serverId] = false;
  $LDAP_server[$serverId] = "CN=administrator,CN=users,DC=xxx,DC=yyy";
  $LDAP_server[$serverId] = "password";
  $query_id = 0;
  $LDAP_queries[$query_id] = 0;
  $LDAP_queries[$query_id] = 'Staff with an enabled account';
  $LDAP_queries[$query_id] = 'OU=Users,DC=xxx,DC=yyy';
  $LDAP_queries[$query_id] = '(&(objectCategory=Person)(objectClass=user)(!(userAccountControl=514)))';
  $LDAP_queries[$query_id] = 'sub';
  $LDAP_queries[$query_id] = 'givenname';
  $LDAP_queries[$query_id] = 'sn';
  $LDAP_queries[$query_id] = 'mail';