Hi, I recently installed a system for a client.  The system consists of a Unifi USG, US16SW, and 4 Unifi NanoHD APs.  The sonos system consists of 1 Sonos ARC, 1 sonos move, 4 Sonos Ones.  All sonos equipment is wireless.  Customer and I were having issues with app acting glitchy.  Sound quality is fine with no hiccups but at times it doesnt connect to the system or the app just attempts to open and then doesnt.  It has been in use for a little over a week.  Yesterday, I made adjustments on the Unifi system.

1. Switch Setup:

2. As many other threads discuss, Unifi switches default to RTSP which is incompatible with Sonos. You need to set the switches to STP.
3. In the Unifi dashboard go to Devices --> Select the Switch --> Config --> Services --> Spanning Tree --> Set to STP.
4. For the root switch (48 port switch in my case) set the Priority to 4096.
5. For secondary switched plugged into the root switch (the POE switch in my case) set Spanning Tree to STP and Priority to 8192.

6. Network Setup:

7. Settings --> Network --> IGMP Snooping: Set to "Enabled"

8. Wireless Setup:

9. Edit the wireless network you use:
10. Block LAN to WLAN Multicast and Broadcast Data: ENABLED
11. Add the Sonos Devices (in my case the 3x Sonos:Connect and the Sonos Play:1) that are HARDWIRED to the swtich to the Excepted Devices list!
12. Enable Multicast Enhancement (IGMPv3) (I honestly don't know if this setting makes a difference or not)

I am now going to allow a few days or so to go with the client using the system to see if anything changes.