Not able to access the private files

Hi All,
I am working on the drupal multisite setup, Here I am not able to access my private files on the subsite.

URL for parent site - www.xxx.com
Private files on parent site - www.xxx.com/system/files/abc.jpg - Working fine.

URL for subsite - www.xxx.com/subsite
Private files on subsite - www.xxx.com/subsite/system/files/prq.jpg - I am getting the page not found error.

Is anybody facing the same issue?

Need your suggestion/guidance to access my private files without changing the subsite URL.

Thanks
Vinoth Kannan