If a Macintosh client attempts to connect to an Acronis Files Connect (formerly ExtremeZ-IP) DFS root volume from a network subnet that is not assigned to a site in Active Directory, you may see this error message in the Acronis Files Connect debug log. "Unable to determine site index for ip address x.x.x.x. This user will not be able to access DFS shares on volume X"
In accordance with the Microsoft DFS specification, access to the DFS namespace is denied for a client if this condition occurs. To remedy this issue, ensure that the Macintosh client's subnet is assigned to a site in the Active Directory Sites and Services administrator tool. For more information on configuring Active Directory sites, see this Microsoft article: Active Directory - Sites Overview