Hi ​@User592998, welcome to the Sonos Community!

I’m sorry to hear that you’re having issues with your Sonos system.

The issues you’ve listed sound indicative of interference or network issues and looking at the case created by the support agent you chatted with, that is what they can see from the diagnostics.

In your post you mentioned you have the Deco XE75 and Deco X50. From what I can see these are a different mesh systems but can work together by using TP-Links Powerline Backhaul, Ethernet Backhaul, or by setting a priority order in the Deco app. Ethernet backhaul would likely be the only supported option here as I’m not sure how the priority order works, you’ll have to check with TP-Link regarding that. Powerline Backhaul isn't supported as this can cause intermittent issues.

While your network may seem fine for your other devices, Sonos need to be able to communicate with each other continuously over the network, as opposed to your phone or computer which often don’t need to communicate with other network devices, just the router. This is why you’ll see network or interference issues on Sonos more than you would your other devices. I would recommend contacting TP-Link to ensure your network is set up correctly and you only have one device acting as the router while the rest of the Deco units act as mesh nodes/access points.

If everything looks fine on the network side, then you’ll want to reach back out to our support team for further troubleshooting. You have an existing case from using live chat which the next agent can reference and has case notes regarding what they need to do next. If you provide your Sonos account’s email they’ll be able to find your case.

I hope this helps!

​@User592998 

I use TP-Link mesh set-up and my Sonos works very well. I connect one mesh node by ethernet to my router - and use the TP-Link mesh in AP mode, so basically all the nodes are talking to the router through the first node. I do not use any of the TP-Link nodes as a router.

Wifi is OFF on the router, so the only signal being broadcast is from the TP-Link mesh nodes around the house. 

The router handles all DHCP/IP address allocation. So Smart DHCP is off in the Deco app. 

NAT is on within the router’s settings. 

As a result, I have a single mesh around the house, all communicating with the router via the first TP-Link node.  

You mention having “TP-Link mesh routers” - it might be just the way you have phrased it but is there a chance they are both in router mode? This could easily cause conflict. I would certainly put all TP-Link in AP mode and connect just one node to your router by ethernet cable, then spread the others evenly round the house. This ensures they are simply all transmitting a single, decent wifi signal with one SSID. 

The Sonos speakers shouldn’t need any adjustment - they should simply all connect  to your single wifi network. If you do follow my suggestion, it would serve you well to turn all your Sonos speakers off before setting the TP-Links to AP mode so that when you turn them back on, they will seek the wifi and then connect. 

Hope this helps...

Hi ​@Rhonny 
 

Thanks a lot for your reply! In fact I don’t use an ISP router, I configured my ISP’s PPPoE settings directly in the Deco app and it works fine. So I have some fiber converter of my ISP directly connected to the main Deco, that connects directly to the internet. 
 

So it is Deco that is acting as the router - but I would expect it to be better at handling it than some cheap ISP router, no?

​@User592998 

Thanks for clarifying your existing router setup. I’m not the biggest expert on these matters but a couple of other thoughts occurred to me, for consideration, but equally may have no bearing on your situation.

If I had two different sets of TP-Link mesh nodes, with differing model numbers, I would use one of the nodes from the latest (or more advanced) model othe XE75] to act as the main router, so that any nodes added from the less advanced model mX50] would still be accepted. Is that what you have done in your setup?

Also, the XE75 is a tri-band mesh which uses a 6ghz band for all communication between the nodes. But the nodes for the X50 are only dual-band and so cannot communicate on the 6ghz backhaul. I would try turning off the 6ghz backhaul in the Deco app so that all nodes, no matter which model, are all communicating on the same 5ghz channel. It might slow some nodes down a bit, but it would make every node an equal, and potentially prevent the mesh from having two differing backhaul methods which could be impacting the Sonos speakers talking across the mesh. 

Those are my thoughts that might help...

Just a small status update: it went a little better sometimes, but then it just got worse again, so despite all my efforts, the issue continued.

This morning I could hardly control the music even on one speaker, so I got desparate and tried enabling and disabling every little setting in the Deco app. Some or what a minute after I disabled fast roaming and beamforming (under Advanced in the Deco app), suddenly all my speakers appeared, I could add a speaker again that had been having connection issues for months, I can group music in rooms again without an issue, and the app is way more responsive. I’m not sure if it was the roaming or the beamforming, but I don’t dare to touch it anymore now 

Just sharing it here, if you have trouble with Sonos devices on a Deco mesh WiFi network, try disabling these two settings and see what it gives… 

I certainly have Fast Roaming off as the speakers are not moving anywhere so once established they don’t need to find a stronger node. But not sure why Beamforming being off would help at all as that ensures a solid connection is sent directly towards your speakers - but if it works for you…! :)