loadByProperties with multiple fields

I want to find a node with some values in two fields. To do that, I use loadByProperties in this way:

$nodes = \Drupal::entityTypeManager()  
  ->getStorage('node')
  ->loadByProperties([
    'field_surname' => 'Surname', 
    'field_name' => 'Name',
  ]); 

This does not work. I am sure that at least one node with such values in these fields exists. This code is used in the .module file. When I debug with dpm(), nothing that I passed inside dpm() is displayed. But when I use this function with only one field, everything works fine. Maybe my understanding of loadByProperties is wrong? How can I find nodes based on values in two fields? 

loadByProperties() requires the entity to match all values. If you want to match 'OR' you need to queries with entityTypeManager and combine the results.

$storage = \Drupal::entityTypeManager()  
  ->getStorage('node');

$nidsA = $storage
  ->getQuery()
  ->condition('field_surname', 'Surname')
  ->execute(); 

$nidsB = $storage
  ->getQuery()
  ->condition('field_surname', 'Surname')
  ->execute(); 

$nids = array_merge($nidsA, $nidsB);

$nodes = $storage->loadMultiple($nids);