Perhaps see the solution in this earlier thread from @sjw 

Thanks - I did see that one earlier, but I have S2 - it’s brand new, and I’m not even getting to a point where I can get any “access denied” messaging. I can’t even enter the information of my synology.

Hi @newsdede 

Welcome to the Sonos Community!

Here’s an example entry from my own system:

In my case, it’s to a Raspberry Pi, so there’s a longer path as compared to the usual NAS setup, which would usually be along the lines of //NAS_Server/music_folder.

I recommend you add a share to Sonos from a Sonos app running on a computer if you continue to have trouble. Please do so by browsing Network rather by using any mapped network drives.

If you continue to have problems, however, I recommend you get in touch with our technical support team who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports.

I hope this helps.

P.S. I am currently trying to find out why the path-entry screen is different, but have been reliably informed that it doesn’t matter if you use forward-slashes (/) or backslashes (\) - either will be accepted.

Hi newsdede,

Have you considered using Plex? When I first added a Synology NAS (220sj) a couple of years ago, I initially tried going the same route that you are - treating it as a Media Server. I eventually succeeded but wasn't happy with the interface. After reading a number of forum posts, I created a free Plex account, connected the NAS music folder and added Plex as a music service via the Sonos controller (Settings > Services & Voice > Add a Service). But for a few minor early glitches, it has worked flawlessly and the album art is perfection (and easily managed via a browser while logged into your Plex account). Something to consider if you haven't looked into it.