Not able to export nodes from one drupal site to other drupal site?
When using content_sync module, you must set the content_sync directory in your settings.php file.

From module description:


  Set the export directory in settings.php. Similar to configuration management, we want to set the export directory for YAML files using the settings.php file.le:
  Use the variable: $content_directories['sync']
  ie:

global $content_directories;

$content_directories['sync'] = '/../content/sync';

  
  Note: set $content_directories as global