Music server cannot be found

Probably not since most NAS options work with Sonos developers spending time and money on a few edge cases isn’t going to pay off for them.

You’d have better luck with your router’s manufacturer, maybe they can tell you where the SMB settings are, what they are and how to edit them. If you can do that the odds of working with Sonos go way up. Lots of SMB settings posts here to look at and try once you are into the router’s config.

If you (or anyone else) get frustrated enough a $15 Pi Zero 2 W is a good option for this. If you don’t have the additional bits needed the kit options are nice too. Just add the Open Media Vault software and you are good.

 https://www.canakit.com/raspberry-pi-zero-2-w.html?cid=usd&src=raspberrypi

Open Media Vault link: https://stan-miller.livejournal.com/940.html

I just wrote to TP-Link:

I am having issues with my Sonos system (v16.1, the latest) doing an Index of my music on my USB Share attached to my main Deco BE63 Mesh. Sonos keeps telling me the USB flash shared drive can't be read to update the Index of the files. I have communicated with Sonos several times and they are unsure what's going on. Media Share is On. Network Neighborhood is On. Deco BE63 sees my USB flash drive. Windows 11 Pro sees my USB flash drive too, in the Network.

What are the SMB settings? Is it SMB v1, v2 or v3? How do we edit them, if possible?

Hopefully you’ll hear something back.

If you have settings questions you can search here to see what has worked for others.

So I did some tweaking to my USB share. Instead of pointing to the Music folder of this drive, I point to it’s IP address and subsequent “g” folder, in the Sonos app’s Music Library.

After I add new music to this USB share, I have to go into the router’s TP-Link Deco app and than to the USB Sharing setting and hit “Scan for USB Devices”. Give it a couple of minutes, and only then can I do an “Update Music Library Now” to re-index in the Sonos app. These multiple steps work 🙄

Also, TP-Link stated this about the Deco 63 Router I am using via email support:
For the SAMBA, Deco BE63 supports V1 and V2. Deco will automatically negotiate with the front-end device. If front-end device uses V1, and Deco also uses V1. This is a built-in mechanism of Deco and cannot be changed, so there are no related setting options.