How can I fix the message "The requested action could not be completed"
from File System service at on-premises data gateway ?

My on-premises data gateway's environment:
OS: Windows Server 2012 R2 Standard
Domain: WORKGROUP - no-AD.
Connect via on-premise data gateway : Checked.
ROOT FOLDER : \
AUTHENTICATION TYPE : Windows
USERNAME : Administrator
PASSWORD : <Administrator's password>
GATEWAY : <machine name>
I want to create my flows with On-premises Data Gateway and File System service.
Regards,
Yoshihiro Kawabata