There are some ubiquity topics here with settings suggestions.

Links form my browser history

sonos ubiquity settings

How to configure your UniFi network for Sonos

I had Sonos plugged directly into UniFi switches for many years, I recall I just disabled STP on the ports that devices were was connected to. If your TP-Link is a dumb unmanaged switch with all wired Sonos devices connected to (ie you dont have any Sonos plugged directly into UniFi), you could try just disabling STP on the uplink port on the UniFi that the TP-Link is connected to.

However in this new ‘Era’ of Sonos devices, where there is no SonosNet or ethernet ports, I reconfigured to a fully wireless (Station mode) configuration, as this appears to be the trend if you have an existing stable and reliable WiFi network.

Thank you @Stanley_4 and @craigski.  I will review the links.

@craigski You’re right the TP-Link is unmanaged.  I’ll double check to make sure STP is disabled on uplink.  

What do you mean about “Station mode”.  Do you mean you unplugged all the Sonos amps from Ethernet?  

Yes, unplug all ethernet, if your wireless is stable and reliable,

“wireless mode” is now described as ‘station mode’ in about my system, previously “WM:1”

https://support.sonos.com/en-gb/article/check-if-sonos-is-in-a-wireless-or-wired-setup

Thank you all!  I’m in wireless mode now.  It’s a little slow to recognize my system when I open the app but seems ok.  

@craigski 

Not sure why but I don’t have WM anything listed.  

Mmm, not sure.

That looks like Android, that I have not used with Sonos. On iOS App I have always seen Wireless Mode (WM) on line after IP address as per:

https://support.sonos.com/en-gb/article/check-if-sonos-is-in-a-wireless-or-wired-setup

Maybe new Android App does not show WM, it does on iOS.