I would expect that this is most likely some sort of wifi interference , with the family room not getting the data when streaming. In particular, I’d be looking at devices that may be too close, especially given your statement about the router being ‘right next to the PLAYBAR’.

Another possibility, although perhaps more remote, is simple duplicate IP addresses, which could easily be tested by a relatively simple network refresh. Unplug all Sonos devices from power, and then reboot your router. Once the router has had a couple of minutes to reboot, plug back in the Sonos devices. If this fixes the issue, it could only be a temporary fix, any router that has handed out bad IP addresses to the Sonos during the Sonos software update process might do so again in the future, so reading the router’s manual and learning how to assign reserved IP addresses for all of your network devices would be a good step. 

Please don’t further factory reset any devices, ultimately, that deletes any data that might help Sonos help you, and as you’ve found, rarely ‘fixes’ an issue, at best sometimes postpones the reoccurrence.

This is just two potential causes for drop outs. Without hard data to look at, I’ve picked out the most likely to help answers, but should this behavior continue,  I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.

I’m having the exact same issue here.  Curious if the OP found a definitive solution.  Zero chance of wifi interference in my situation so Alex’s suggestion above would not apply.  I’m on google wifi in a major downtown area.  Signal/interference is never an issue where I’m located and the irony is the strongest signal and router location are in me Living Room, yet, like the OP, my LR speakers are the ones that keep cutting out while all the other bedrooms and living spaces place without issue.  I also did a reboot of my router.  All my speakers and the app are on current software updates.  The LR has been cutting in and out has been ongoing for the past two weeks and would love to hear any feedback.

What did Sonos support say, when you submitted a diagnostic, and called them with the diagnostic number?

For what it’s worth, I can’t think of anywhere more ripe for wifi interference than a Google WiFi situation in a downtown area, but if you’ve checked the signal interference from outside networks, you know best. I’d still suggest that duplicate IP addresses could be an issue. A reboot of your router simply does not fix that issue. But Sonos support is likely your best bet, as I suggested in my first response.  

What bites a lot of folks is looking at WiFi signals to see if there is WiFi interference.

You need to look at ALL the RF energy on and near your selected WiFi channel to see if there is an issue. Non WiFi signals, like baby-monitors or just plain old RF noise don’t show on a WiFi signal monitor, yet they will happily trash your WiFi signal.

I don’t know of an inexpensive way to do that unless it is built into a device you already have. Ubiquity APs have it available and I’m sure others offer it too.

I have the same issue and it only happens to one of my speakers. I have three Sonos ones and the one that is not part of a stereo pair cuts in and out for no reason. I have great Wi-Fi connection all throughout my house.  Frustrating.

Have you submitted a system diagnostic within 10 minutes of experiencing this problem, and called Sonos Support to discuss i?.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Physically move the problem speaker. WiFi interference is often very location specific.

Having the same issue here, but with a strange twist. One room (out of six) continually drops out here at our workspace. It happens frequently when streaming with Plex, Amazon Music, Bandcamp, Mixcloud  or Spotify. However, we hardly ever see the issue with Sonos Radio? Which implies that it is not merely a Wifi issue? Why would Sonos Radio have a more robust service? I’ve noticed this over many weeks...

What data rate is each service using? WiFi issues that don’t impact lower rate connections can choke on higher rate ones.

Maybe try playing some local files, first in lossless FLAC or other codec and again in something lossy like MP3 and see if both work.

We've had our Sonos system for 6 years and started having problems with a few zones intermittently cutting out while the app on our iPad shows the music is still playing. This problem started a few months ago and our audio tech has made sure our software is up to date but the problem still persists.
 

we have no WiFi issues with our various other WiFi connected devices and our speakers are hard wired to our aidio room where our Sonos devices are housed.

i wonder if the connection issues are a result of Sonos software updates ,which may be designed for newer devices but are making older units malfunction? This seems to have happened recently so I doubt that we are all having WiFi or connection issues.

when the S2 app upgrade occurred a few years ago, several of my sone devices were not supported but after complaining for a week they suddenly were included in the software upgrade.

Thoughts? 

Since you are sure it isn’t your network you are probably best off collecting a diagnostic when you have your next issue. Call Sonos support with the number it provides and see what they can see.

A lot of issues are network related, even if that doesn’t seem possible so trying the suggested steps to check that can often solve an issue.

https://support.sonos.com/en-us/article/improve-your-sonos-products-wifi-connection

It seems unlikely that the issues are due to Sonos’ software. Sonos does exercise your network substantially more than most other network devices, due to their need to intercommunicate constantly. My guess would be that there is just enough wifi interference to cause random issues with your Sonos, or even duplicate IP address issues on your router. 

For what it’s worth, I’ve found no real relationship between the graph bouncing in the controller, and anything actually playing on my system, at least not directly. 

I’ve never seen Sonos release a product, since they’ve been in business, without first releasing an updated controller that contains that speaker’s definitions in the new software. Which speakers did you have that Sonos hadn’t released software for? Or are you getting access to Sonos devices before they’re released for sales?

This is happening to me now…found this thread, same issue. Sonos in 5 rooms has been working fine for many years and just starting having this cut outs. Nothing has changed in my home. Internet and WiFi working great and I live in the country, no interference near me… Guess I’ll be calling support! 

Recently started having this issue where particular rooms with the Playbar and Sonos ones will drop audio will the other rooms will keep playing. I submitted the system diagnostics and contacted support. 

The response:

there is an issue with the Family Room, specifically the Playbar, that is not connecting properly to your WiFi. The issue is when it request for the WiFi channels on your WiFi and it is unable to pick the required information on the system, so it ends up affecting the system and causing this audio issues. We are aware of this issue and are investigating. At this time, rebooting this device is the best way to alleviate this issue. We do not currently have an ETA. 

Thanks a lot for reporting this, since this help us investigate what can be causing the issue with the diagnostics and all the information provided.

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I did reboot my Playbar and Sonon One's as requested. I have been up and running for about 30 mins without dropping audio, so hopefully resolved for sometime.

So if this is happening, please submit the diagnostics so they can hopefully resolve this permanently.

S2 is broken for older S2 compatible devices and the only solution (until Sonos fixes it) is to revert back to S1. 
 

Over on the architectural forum there has been a gathering momentum around the fact that Sonos broke S2 for older devices back in the summer of 2023. 

This has taken a long time to come to light because each reporting of ‘my system is dropping out and my devices can’t be found or won’t connect’ is met with derision by forum members and the insistence that it’s an environment issue  

Sonos has finally admitted that there is a problem affecting Gen2 Connect and Connect amps  

It looks like the problem is affecting older speakers too.

So if you have this problem, revert back to S1 until Sonos fixes S2 for older devices.