MR60 Router and Plex?

I am a Mac user who recently switched from using the Nighthawk RS9000 to the MS60 Mesh Network due to buying a larger home. I own 4 iMacs and run 4 satellites MS60 to cover the entire property (10,000 sq ft). My Cloud PR4100 (40TB) is attached to my MR60 Router and is used for storing movies (my retirement project). 

I can see and access the PR4100 on my network. However, Plex Server does not recognize it. Does anyone have a solution for this? I called Western Digital yesterday and the Tech said there is no problem on their end, the PR4100 is running as designed. Thanks, Vern