Maybe this thread contains an answer for you: 

Thank you for your response @106rallye . I had seen that but it talks about size of playlist not number of tracks:

Upon further checking on this, Sonos has playlist limitations.

• General 10k track limit (total for all playlists)
• Spotify: 6.75k (+/- depending on metadata)

Based on that information, I broke up all of my original Spotify playlists into 4k or lower track segments but I still get the “Unable to add songs to Queue” error message. That thread is a year old and locked. So I opened this new one.

Sonos applies a time limit of ~15 seconds to any queue loading operation. If the playlist is too large, or the service too slow, it can result in the error message you saw.

Which includes time outs due to interference between your speakers and your speakers and the router. 

Thanks @ratty and @Airgetlam,

Understood, and I also realize there are multiple factors that could contribute to that kind of latency:

WiFi strength: Could be part of the issue on my iPhone, but my PC where I am running the Sonos desktop app is connected via ethernet cable.

Issues with my router and/or the cable company’s modem: I just went to speedtest.net on that same PC and I am getting:

• Ping: 3 ms
• Down: 304.98 Mbps
• Up: 344.44 Mbps
• That seems pretty robust in my opinion

Latency issues caused by Spotify’s response time:

I don’t have any good way to measure that but:

• The Spotify desktop app on the same computer can build a queue based on one of the playlists with 4k songs in under 2 seconds even after deleting the Spotify client cache using the instructions at https://community.spotify.com/t5/Desktop-Windows/cache/td-p/4722569.
• I realize that may not be an apples to apples comparison though because the Spotify app seems use a method that builds the queue in a rolling fashion; 100 tracks at a time.
• Based on some experimentation, the Sonos desktop app seems to build the entire queue all at once.
• Based on the same experimentation, the Sonos app threw the “Unable to add songs to Queue” error at 2,045 songs but was able to load at 2,044 songs.
• Based on other things I have read in this community forum, I suspect that the exact number varies based on amount of metadata.
• Interestingly, the Sonos app threw the “Unable to add songs to Queue” error in less than 10 seconds after I right clicked on the playlist and choose “Add to queue”.
• I was also able to play that same playlist from the Sonos app on my iPhone which probably rules out WiFi bandwidth issues.
• However, I believe I also read somewhere in this forum that playlists get cached on the speaker itself. So, maybe that was why I was able to start the playlist from my phone after I had already run it from my desktop app. But maybe not.

I guess my bottom-line questions now are:

1. In general, should I expect to only be able to use Spotify playlists that are around 2k in the Sonos desktop app?
2. Should I expect similar thresholds in the Sonos mobile app?

Well, I can say that 2) shouldn’t make any difference. The controller is merely a remote that is talking to the app that’s running on your speakers, so whether it’s a PC/iOS/Android/Mac controller shouldn’t make a difference. 

What can make a difference is which device/speaker is running the operation. In general, you want it to be a wired device, and newer (more memory, better CPU) than an older device. Wired reduces interference possibilities, although doesn’t obviate duplicate IP bouncing, but many people incuding myself, have no issues with larger playlists on wireless connections. I happen to use SonosNet, but the BOOST isn’t capable (I think!) of running this kind of operation, it requires a “player”. 

But then again I’m not sure how to force it from one processing device/speaker to the next. I suspect @ratty knows that, though. 

I’m unsure of the question. If it’s about the location of the GC (group coordinator) node it’s in the first room of the group. Juggle the group to suit.

If the first room is a home theatre setup the GC is the master player; if the first room is a pair then the GC is usually the left unit, but it depends how the pair was assembled (check for the top one in Settings/System/{pair_room}/Products).

The former was the answer I was unsure of.

Under the assumption that it’s the group coordinator that does the processing of the library files from the service, which makes sense.

Thank you most kindly. 

Yes the GC owns the queue.

When I go to Settings/System the first device listed is my Sonos One named “Basement”. “Basement” is connected to my router via an ethernet cable. It was the first device that I set up (at least a year ago). If I am following the discussion correctly, this would be the GC, correct?

The devices in my system are:

• The Sonos One named “Basement” described above
• 2 additional Sonos One (i.e. 3 total)
• 1 Move
• 1 Play: 5

None of these speakers are configured as a pair nor is my system set up as a home theater.

Yes, it would be the group coordinator. 

A Sonos One is a good device. I’d double check to ensure that you’ve assigned it a reserved IP address, since it’s wired, that’s pretty much the only possibility for network congestion. You’re looking at anything that might interrupt that 15 second time limit, IMHO. That’s the most likely one for a wired device.

Given the router, it’s not uncommon for the process of a Sonos software update to cause the router to hand out a duplicate IP address, but it’s up to the network as to how frequently that interruption can occur, too. 

There’s the temporary solution for duplicate IP addresses, which is unplugging all Sonos devices from power, then rebooting the router. Once the router comes back up, plug back in the Sonos devices. The challenge here is that if the router has failed in this fashion once, it could again, depending. The more permanent version of this is setting up reserved IP addresses in the router’s DHCP table, something that’s fairly easy to do, once you’ve read the router’s manual. Took me 5 minutes to understand how to do it for the first Sonos device, but after that, it was about 30 seconds per, and I did it for all of my network devices, and allowed some “headroom” for guests (technically, basement room….started all my Sonos stuff at .100, left everything below for random connections).

But @ratty has much more intimate knowledge in this area than I do, and a wider experience in networking across the board. Pay much more close attention to his comments than mine. 

@dan37,

If you want to make the playlist public (temporarily) and post it’s URL here, we can perhaps give it a try and see if we can load all its tracks on our own devices... I’m just not sure if we are able to access that with a free Spotify account, but if so I’m happy to give that a try or PM the URL to me, whichever you prefer.

@Airgetlam 

Thank you. However, I already use static IP addresses for all my devices. I looked at the table of currently attached devices and there are no duplicate IP address assigned.

@Ken_Griffiths 

Thank you as well. Here’s a link to a playlist that is timing out. I have temporarily made it a public playlist.

There may be some misunderstanding. The Group Coordinator is not the first room alphabetically, nor the first device that was originally installed. 

The GC is in the first room in any group -- to which other rooms are added -- and relates only to that specific group. Its job is to fetch the stream and distribute it to the other group members. As such its location is dynamic, depending on the composition of the group, and of course there will be multiple GCs if there are multiple groups. 

@ratty can you confirm my understanding that the GC, in sonosnet, will then route its requests to retrieve data via a wired component. And therefore the quality of that link matters well.

Yes. That’s its connection to the outside world. You may wish to refer to the Network Matrix at http://IP_of_a_player:1400/support/review to determine the active link and its signal strength.

Dan,
Well the "xxxListening List 002 Temporarily Public” shared playlist does load and begin playing for me in Sonos, however I just cannot see the track-list in the Sonos room queue, as I only have the free version of Spotify, but I do see the track list in Spotify… it is streaming okay here.

If someone else here has the full subscription version of Spotify, they maybe able to test it and see the list of tracks in their room queue. HTH

I have Spotify Premium.

I’ve tried adding the 4k Spotify playlist to Sonos multiple times and get the queue error after 9secs.

Thanks @Mr. T - sadly I can’t assist further without subscribing, but maybe one or two others here will be able to check it too.

I assume the metadata in the playlist is too great given that I receive the queue error after circa 9 secs.

A “queue full” error says just that. I just quickly threw a composite (some Amazon, some local) playlist into the queue repeatedly and got a “queue full” message at about 48k tracks, of which some 21k were from Amazon.