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The Ninth
The Ninth
Collaborator I
April 25, 2026

Sonos Amp becomes unreachable on UniFi after some time (no ping / no ARP, link still up)

  • April 25, 2026
  • 22 replies
  • 560 views

Hi everyone,

I’m running into a recurring issue with my Sonos Amp in a UniFi network and wanted to check if anyone has seen something similar or has a working setup with current UniFi firmware.

Setup:

  • Sonos Amp

  • Ubiquiti UniFi network system (UDM Pro + switches)

  • Amp connected via Ethernet (also tested via WiFi)

  • Flat network during testing (no VLAN separation)

Problem:
After a reboot, the Amp works fine. But after some time (hours to days, even when idle), it becomes completely unreachable:

  • disappears from the Sonos app

  • cannot be pinged

  • does not respond to ARP requests

In UniFi, the behavior varies slightly:

  • sometimes the device is still shown as connected but greyed out

  • other times it disappears entirely as a client

  • however, the physical link LED on the switch port remains on

Only a full power cycle brings it back. Replugging Ethernet alone does not help.

What I already tried:

  • Ethernet and WiFi (same behavior on both)

  • Disabled WiFi when wired

  • IGMP Snooping + Querier enabled

  • RSTP enabled, STP Edge on the ports

  • Forced 100 Mbps Full Duplex

  • Disabled PoE on the port

  • Tested different cables and switch ports

  • Monitoring via ping (device stops responding entirely when the issue occurs)

From what I can tell, when the issue happens the Amp stops responding at a very low level (no ARP replies), even though the physical link remains up.

Background:
Interestingly, I had a very similar issue about two years ago. Back then I was able to resolve it by adjusting some UniFi settings (related to multicast / network behavior).

However, after various UniFi updates, those settings either changed or are no longer available in the UI, and I haven’t been able to reproduce the old working configuration.

Question:
Is anyone currently running a stable setup with the Sonos Amp on UniFi?

  • Are there any specific UniFi settings (current firmware/UI) that are known to fix this?

  • Has something changed in how Sonos interacts with UniFi?

  • Or does this sound like a faulty device after all?

Would really appreciate any insights or current best practices for Sonos + UniFi.

Thanks a lot!

Robert

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22 replies

Airgetlam
Airgetlam
April 25, 2026

You’ve read this thread? 
 

 

 

Bruce
buzz
buzz
April 25, 2026

Don’t wire any SONOS units to the UDM PRO because it does not support STP. Yes, I know that there is an STP setting in the PRO, however, this is a default to be passed on to the switches. Set this for STP.

In my experience UBIQUITI updates can break things. Have you reserved IP addresses?

The Ninth
The NinthAuthor
Collaborator I
April 25, 2026

You’ve read this thread? 

Yes, I’ve mostly followed these recommendations, especially the “golden rule”. All my Sonos devices are wired.

The only difference I noticed is that I was using RSTP instead of STP. I’m not sure if that makes a difference in a fully wired setup, but I’ve now switched to STP to match the recommendation and will observe if the issue occurs again.

Don’t wire any SONOS units to the UDM PRO because it does not support STP. Yes, I know that there is an STP setting in the PRO, however, this is a default to be passed on to the switches. Set this for STP.

In my experience UBIQUITI updates can break things. Have you reserved IP addresses?

All Sonos devices are wired to a UniFi Switch 24 PoE.

The affected Sonos Amp has a static IP address.

I already had a similar issue about two years ago and was able to resolve it back then. It seems, as you mentioned, that a UniFi update may have broken that setup again.

The Ninth
The NinthAuthor
Collaborator I
April 25, 2026

Changing the spanning tree protocol to STP and adjusting the switch priorities did not help. The issue reappeared after about one to two hours.

buzz
buzz
April 25, 2026

I once had symptoms that an ancient NAS was failing, but the symptoms were intermittent and not quite what I expected for a failing drive. After a while I decided that the symptoms suggested a duplicate IP address … but I’m too smart for that … right?!! Eventually I swallowed my pride and checked for duplicates … darn! A few weeks prior I had reconfigured my network slightly and updated all of the address reservations. Unfortunately, I had forgotten about a palm sized device hidden in a cabinet, using a fixed IP address that formerly had been outside the DHCP range. It now duplicated the reserved NAS address. This was certainly not UBIQUITI’s fault.

The Ninth
The NinthAuthor
Collaborator I
April 25, 2026

It is not related to the IP address. I started with a DHCP-assigned address and then moved to a different, static IP address. The problem stayed the same. 

Pools-3015
Pools-3015
Prodigy I
April 25, 2026

Do you also have mDNS enabled? While I do not have my Sonos speakers on my trusted network, it is still enabled. May make a difference for you.

I also use RSTP with priorities set for main and downlinked switches. They should be set correctly if you have speakers wired to more than one switch.

There is also a great guide to check your settings with found here:

https://github.com/IngmarStein/unifi-sonos-doc

The Ninth
The NinthAuthor
Collaborator I
April 25, 2026

I ran another test to further isolate the issue: I connected a small unmanaged switch (different brand) to my UniFi switch, and then connected the Sonos Amp and another unrelated device (a printer) to that switch.

The result was quite interesting:

  • the Amp disappeared again shortly after

  • the printer remained connected and reachable without any issues

This suggests that the UniFi switch itself is not blocking the port.

At this point, I think there is a real possibility that the Amp itself is becoming unresponsive or crashing. However, I am not sure how to narrow this down further.

Has anyone seen similar behavior or has ideas for additional tests?

MoPac
MoPac
Headliner III
April 25, 2026

PoE can damage non-PoE devices like the Sonos Amp.  Not sure if that might be the cause of your intermittent connection issue.  I always use “dumb” non-PoE switches.

Stanley_4
Stanley_4
Grand Maestro
April 25, 2026

Different types of POE sources, some can be damaging while some are safe. Some source devices offer both modes and an error in configuration can be expensive.

Beyond my skill level but if you look for "standards compliant" and "passive" POE you should find details.

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