These are great explanations, but the OP is still running Roon Core+Control on his iMac. The Innuos ZENith does not have Roon Core capabilities (but does UPnP server duties and storage) as far as i know. (Added in MkII?)
So basically, the only thing that has changed is that @Matt_Cuttler has moved his media files to the ZENith? If this is wrong i apologize.
I’d recommend returning the ZENith and instead going for a NUC7/8 i3 and adding an externa USB drive with media files. Install ROCK and you are ready to move the processing to that machine.
(Or go for the MkII series of Innuos)