we are working for the active directory aunthetication in dotnetnuke and we have done it successfully but there is a problem which can be more clear with the following picture and information below the image.we configure the active directory for the “DNA_NTD domain” and the “DGIWEB” is the server name.

Note that the user “dgiwe” doesn’t exist in our DNA_NTD domain (yet it is a local user on the DGIWEB server. Additionally, the domain it is attempting to use (the server name) is incorrect.
This is expected behavior, since the user account isn’t a domain account it is reflected as a “Machine” account which that distinction is done by putting the servername in for the domain.