Sonos play 1 not connecting to new mesh wifi network

The easiest solution would have been to use the same SSID and password from your old router. Then you may have only needed to reboot the speakers to get them working again.

Did you make sure the existing router was configured to bridge or passthrough mode? There should only be one device in your network doing routing. If there are two devices, the issue you are describing will happen.

what is the model of the existing router? 

Thank you ​@Mr. T. Unfortunately tried your suggestion and play 1 speaker (not connected via ethernet) is still migrating to solid white light after connection (i.e. no green light showing) - so factory re-set not completing properly.

I have another suggestion on network settings (for my mesh network), so will look and see if that is the issue.  

If not, then I’ll contact Sonos support, because as you point out, it should be possible to factory re-set the device. Thanks for your help

Thanks ​@Pools-3015. Router is Adtran 854 and broadband provider is HeyBroadband. New mesh system is via Tp-Link Deco device.

Yes SSID and password I kept the same as previous wifi network. Router is in bridge mode, but previous wifi network is still visible, so I will get in touch with my Broadband’s technical team, as the written instructions they provided were not that specific/didn’t include steps to turn the old wifi off

A solid white LED implies the speaker is powered up and functioning correctly.

Does that speaker show up in the Sonos app after your attempted factory reset? If so, what network is it connecting to?

Thanks ​@Mr. T. No the speaker doesn’t show up.

If I switch my phone & sonos app onto the old wifi network, the 2 speakers were showing up there, until I removed the old network (under manage networks) in the sonos app, as that’s what one of the help articles advised. So I guess it could mean that although the app is not detecting the old network, the speakers still are..

You definitely only want the Deco mesh to be broadcasting a WiFi network, with no WiFi signal coming your Adtran router.

You obviously have two networks broadcasting which is the old router and your new mesh. The old router by all accounts is not in bridge mode.

There should be an FAQ for the mesh network you purchased on how to remove the old router and use one of the mesh units as a router and the others as satellites. Be sure to power down your Sonos first and use the same SSID and Password as was used with the old router.

​@MattT9 

I have my TP-Link Deco mesh running in AP mode, not router mode. The router remains the router. (I have turned Smart DHCP off in the Deco app so the router continues to handle IP address allocation.) 

I turned the 2.4ghz and 5ghz wifi off on the router, so only the mesh nodes broadcast the wifi. 

10+ Sonos speakers connect perfectly to the various nodes. Sonos app remains super quick.

​@Rhonny thank you - yes have subsequently turned off both the 2.4 and 5ghz wifi on my Adtran router, so no longer broadcasting a signal (let’s just say the instructions on how to do this from my broadband provider previously were lacking). Will try and factory re-set the play 1 speakers tonight to see if I can then set them up on my new mesh network. 

If not, will try the additional settings tips you suggested - thanks 

​@Mr. T, ​@AjTrek1, ​@Pools-3015 and ​@AjTrek1 thank you for all your tips - finally have reached a resolution. Combination of disabling old wifi, putting mesh into access point mode and contacting Sonos support for factory re-set of both products has resolved the issue. Great to see the power of the Sonos community in resolving issues. 

I have more than 20 Sonos speakers and many other devices in my LAN, either wired o Wifi.
In my Sonos system, I was having problems streaming music from Spotify, Apple Music and others; also it was almost impossible to listen to any Sonos Radio. Starting a list from Spotify was very slow and not reliable. Slow list loadings or with errors (10001, 1002...); and speakers grouping were also common problems.

After many interactions with support people, we stated that there were no problems with Sonos ecosystem.
Then, I realized I was the problem after installing a TPLINK mesh Deco. 
Skipping the -very long- resolution process, the final configuration that is working fine and smooth is:

1. Internet provider-->Modem (passthrough)→ Deco Router-->Other Deco Mesh devices-->Sonos and other devices.
   Important Note (added by Sonos Support): Cable just one (no more) Sonos speaker to the router. In this way, Sonos will use Sonosnet for Sonos traffic.
   If you cannot wire one speaker to the router, Sonos will use your wifi in full.

2. If case you cannot switch the modem provided by your Internet company, another possible conf is:
   Internet provider-->Modem (ROUTER (default))→ Deco (Access Point)-->Other Deco Mesh devices -->Sonos and other devices.
   Important Note (added by Sonos Support): Cable just one (no more) Sonos speaker to the router. In this way, Sonos will use Sonosnet for Sonos traffic.
   If you cannot wire one speaker to the router, Sonos will use your wifi in full.

After making all the changes, I re started all the Decos and internet modem and after tested the Modem and the Deco were working fine, I turned off not only the Decos again, but also I turn off the full house (main electricity breaker), waited 20 seconds or more, and then re-energized everything. This forced all the devices -Sonos speakers included- to ask for a fresh IP address).
All was working perfect and smooth!
Then, I stressed the Sonos system with all the previously not working functions and everything was and are working smooth and really fast!

(After a couple of hours I reinitiated by its app, all the Deco System, and the Internet speed measured at DECO level improved a lot, about 70%. I don’t know why.)

I assume this configuration could work in other mesh systems, but I didn’t tested.

Hope it helps!

Side note: To explore the Sonos environment, I recommend the use of the following URL, from your LAN: http://aa.bb.cc.dd:1400/support/review, where aa.bb.cc.dd is the local ip address of any of yours Sonos speakers.  (Thanks, BSteiner!!: “The last line, “Network Matrix” is the grand prize for Sonos diagnostics.).
Don’t spend time understanding the network matrix created: Copy-paste the image to your favorite AI app (in my case Gemini) and it will be interpreted for you. The recommendations provided were really useful.

​@CEJL 

Great you resolved your issue.

It appears you placed your ISP router/modem combo into Bridge mode for the router side. Then connected your Deco to the ISP modem. Although you seem to have offered two solutions I'm not completely sure of my analysis of your post. What I am sure of is that you previously had two Wi-Fi networks in play which caused the problems.

Keep in mind the Network Matrix is a legacy page and newer Sonos aren't fully supported. Still it is interesting to look at and I'd love to see an updated version that supported all Sonos devices.