Welcome to the community I'm sorry to hear the connection for your NAS player doesn't seem to be working correctly. I'm not an expert on these things but I'll certainly do my best to help get to the bottom of the issue.
Out of interest, when you see the "Media Server Loading" message, are both the PC and NAS device showing a connection through the hub? If there's a loss of connection are you noticing any other devices struggling to connect at the same time? Do you manage the connection between the NAS device and PC through specific software or do you just have it set up as an additional drive? It might be worth checking for latest drivers etc if it's software.
Let me know as much as you can, I'm sure we'll get to the bottom of things with a bit of help from @Kippies and others as well
Here is what I have done so far, after trawling through countless sites on the web,
The Marantz player has DHCP turned on and on the SH2 i have set a DHCP reservation for the NAS and also 1 for the PC.
I have also put the NAS ip in the DMZ. I have plex set up as media server with the Music folder on the C drive as the main music folder and things have been ok (touch wood) for the past 2/3 days, however if there is anything I have done wrong or there is anything else that You think may help please feel free to let me know
I have also gone into services manager and set the following list all to Automatic as most were disabled,