trying to install plex manually on 5N2



While attempting to drop the plex update into the "DroboApps"folder...

My home domain prompts me to authenticate on the "home" domain. If I type ".\admin" it just switches to "Domain: Local Computer" I cannot get it to authenticate. Do I need to type something like, "Drobo5N2\admin" ? Why can't I authenticate? I know the correct user/PW because I can login to Dashboard fine. Also, it should be mentioned that I have Windows default Security Policy. Does it need to be edited? I'm so fustrated!

Drobo 5N2 (current firmware)
NUC 7 (i5 running Windows Server 2012 R2)