Did you remember to enable SMB v1 on your NAS? Sonos won’t connect without it being available.

Yes Smb 1 is enabled.

Try adding it in again to generate fresh error logs, submit a diagnostic and contact Sonos with the number, they can see log information we users can’t.

For all it is worth, I was getting exactly the same message.

Then I explicitly typed in the IP address of my Buffalo Linkstation and it worked.

Is Free NAS a physical local drive, or a virtual web based connection?

Airgetlam,

In my case (Buffalo LinkStation) it is a physical local drive, connected to my router. The router assigns a standard IP to the NAS drive. I mapped it easily enough on my PC but then it stopped working on Sonos and so I removed it and then added it again using the explicit IP: \\192.168.1.4\share\music

Curious as to why you’re using Free NAS 11.3 rather than the supplied software from Buffalo? I’d think that might be part of the issue.

Ah, you’re not the OP. In your case, I suspect the router assigned it a new IP for some reason, and the system/router was not translating the name to IP properly.  

Airgetlam

Good point. I do not really know what I am doing. Just hacking around.

I tried to remove the drive and then add it again typing the same path as before. Sonos did find it, but it said it was denying access. Go figure. 

Then I typed in the IP explicitly (after finding that tip on some other thread around here) and it worked. I candidly admit that I do not have the foggiest idea of what is actually happening ;-)

Laugh. In that case, I’m not 100% sure I do either, but it sure sounds like a translation table error. But I’m glad you were able to resolve it.