I have a Sharepoint 2013 Server in our DMZ (non-Domain joined). Then I configured an Active Directory Import from our LAN to this DMZ server (so that we have our domain credentials to connect to the sharepoint sites).
After the import, I could see the User profiles in user profile service application - manage user profiles. (Example:)
Now I wanted to add this User to a Site. When I go to Site Settings - Site Permissions - Grant Permission I get the following error:
How can I add my users correctly to my Site? I really hope someone of you can help me.
EDIT: I share my screnario, so it's easier to understand.
I have a Sharepoint 2013 Server in our DMZ (non-Domain joined). Then I configured an Active Directory Import from our LAN to this DMZ server (so that we have our domain credentials to connect to the sharepoint sites). The server is accessable from the internet and the goal of the server is, to provide a data storage with onedrive for business.