I have tried everything...Literally...

Yes, I will update later today with the results 

(edit)

*Update* - L2 Support is saying that my Mid Left Studio is experiencing “Streaming Underflow”, so they want to hardwire that to ethernet, then add each speaker 1 by 1 to determine the threshold of the Group which they are saying is only about 5 speakers before dropouts begin. 

Sounds like plan. Hopefully you can wire the speaker depending upon distance to router.

I noticed something strange which I can consistently replicate. The Dropouts and Track skips are only happening on Spotify...we tested Sonos Radio and for hours perfect. Then we added Apple Music and began streaming from it, flawless. Switch back to Spotify and its all over the place.

I would get error messages at the bottom of the Sonos app saying things like “Connection to Spotify was lost” or “Track cannot be played - not encoded correctly” and just keep switching tracks and dropping out. 

If the audio issue I have been having was related to a connection, an interference or Wifi issue, it should persist across all platforms because the interference or signal issues is Local here to me. This is leading to me that somehow this is a Spotify issue? Thing is Spotify plays perfectly on the phone or BT speaker. Could the issue be between the Spotify and Sonos servers not communicating properly?

There really aren’t any ‘Sonos servers’ for Spotify content. When you select Spotify in the Sonos controller, your speakers reach out to a server operated by Spotify, on which Spotify has implemented the Sonos API. This usually (not sure with Spotify, but would be stunned if not) is a separate server than in use for Spotify’s normal app.

I tend to agree with your conclusions, and would certainly press my complaints to Spotify. I have to imagine they’d take a paying customer’s complaints with more seriousness than random feedback from a company like Sonos who has no financial relationship with them. 

Based on this discussion, your system had very poor connectivity. Directly playing Spotify on your phone uses a different set of network resources than multiple SONOS players.

You need to improve connectivity. Consider the possibility that you have a defective player that is poisoning the wireless environment. The diagnostics are the place to research this, but you could bring the players online, one by one, while checking the Matrix. When the rogue comes online, the Matrix will go sour. Remember, the Matrix is static.

@buzz Yes exactly, what you are mentioning is the current test we are running w/support. One by one bring the speakers online, then run a diagnostic after each, with the test including one speaker actually being hardwired (with and without the boost). 

Keep you guys posted!

I found solution...kind of

Sonos support said that: “ ‘Stream Limit detected for Music Service on Sonos’ A stream limit error is a failure condition that occurs when multiple streams are initiated from the same account. When this occurs, the music service terminates the oldest audio stream to allow the newest one to play”

We have 10 teachers and their Spotify accounts are all loaded onto the Sonos Account, never an issue for the last 1 year and 4 months, but now is apparently?

Well here is the Solution I found: The issue to me now seemed pretty isolated to Spotify. After testing Sonos Radio, today I had a teacher add her Apple Music to Sonos and she had 1 playlist and the entire thing played through with Zero issues, none. So it dawned on me to try to play the audio via the Spotify App then select the Sonos as a “nearby Source” and bam the audio started piping through as expected, but to my surprise not a single drop, nada, it was absolutely perfect. I went and opened the Sonos App then for finite control of the audio (cause Spotify’s audio control is terrible) and it has full control, shows the album art and everything, the thing it does not show is the track list, it shows an image saying “Audio started on Spotify” and a big End Session button.

What does this mean? Pretty clear to me based on what is happening...it’s not Spotify, not Sonos, but when Spotify runs through Sonos as a Service, the issues begin. Sonos has their most Senior and Management team trying to assist and remoted into my PC to see if they can test their Spotify account, the issue was immediate with their account too.

Simple question…I think 🤔…

So you’re saying the when Spotify is selected as a service via the Sonos app it skips (or stops) based upon the high number of individual streams…correct???

I don’t use Spotify therefore I have no experience. However, the same is true with Amazon music… unless you have a family or business account multiple streams started by different individuals will stop the music. So is that what occurred in your situation?