SearchApiException on index

Dear people,

I note that the use of the searchAPI in our Drupal installation takes quite a long time. It appeared that the query is inefficient. In the watchdog log, I see this error message for every search request:

SearchApiException: Required field search_api_access_node not indexed on index Default node index. Could not perform access checks. in _search_api_query_add_node_access() (on line 2104 of /sites/all/modules/search_api/search_api.module).”

The code arround that line:

// Check whether the necessary fields are indexed.
  $fields = $query->getIndex()->options['fields'];
  $required = array('search_api_access_node', 'status');
  if (!$is_comment) {
    $required[] = 'author';
  foreach ($required as $field) {
    if (empty($fields[$field])) {
      $vars['@field'] = $field;
      $vars['@index'] = $query->getIndex()->name;
      throw new SearchApiException(t('Required field @field not indexed on index @index. Could not perform access checks.', $vars));


What is the cause and how do I solve this?
Thank you!


Drupal version: