Two identical Sonos One HAY speakers lose Wi-Fi connection in the kitchen

If this issue is only happening in the kitchen, that points to network interference. Kitchen appliances are notorious for inducing interference or blocking radio signals from your router or AP. Since you have done most of the troubleshooting and found that an Ethernet cable solves the issue, is there an easy way to make that permanent? 

If so, thats the solution I would use.

I just did that recently to help an Era 100 stay connected. It is the furthest speaker from my AP and moving it was not an option.

It is not really close to my fridge, gas stove and exhauster, weird if that should be the case, it happens when these are idle as well.

Not possible to cable this, then i would have to drill holes through 2 walls and cabinet.
All the other sonos that works fine, are connected to the same router, through thicker walls.

To add, this problem also happened with the other HAY speaker when it was in the bedroom (which is not permanently connected with cable since 2m from router in same room) so maybe not the location that is the issue.

Connect it over 5GHz and block it from accessing the router’s 2.4Ghz band.

I would use 40MHz channel width for 5GHz.

If that does not help, try disabling 6GHz to test.

​@andersmarc, Is the TP-Link Deco XE75 set up correctly as an access point, i.e., is it not accidentally running in router mode?

How to change the Operation Mode in the TP-Link Deco App

1. Open the Deco app on your smartphone.
2. Tap the More icon (three lines or the grid icon) in the bottom right corner.
3. Select Advanced from the menu.
4. Tap on Operation Mode.
5. Choose Access Point (or Router if you need to switch it back) and save the settings.

Note: The Deco units will reboot automatically to apply the changes.

​@Mr. T - I have already tried having this isolated to either the 2,4ghz first and 5ghz band after, issue persists.

​@craigski - only 80mhz and 160mhz available for the 5ghz network, but if the Sonos One is on the 2,4ghz, then probably no effect to change?

​@Smilja - My Deco is currently in Wifi-Router mode.
The internet connection is supplied by Parknet through a managed switch in the basement and an Ethernet wall socket in my apartment.
There is no modem/router in my apartment before the Deco.
A computer can obtain internet directly from the wall socket, but the Deco is the only router protecting and managing my private home network.
So would the AP solution be advisable here still?

Also, check this setting:

 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 😃

Interesting, will try this and report back first. Since I have only one Deco in my setup, no need to have it enabled, lets see what it does.

Set to 80MHz then, plenty of whitepapers/articles describing the downsides of 80/160, eg:

https://eyenetworks.no/en/recommended-channel-widths-for-home-wi-fi/

Which Bandwidth Is Recommended As A Standard For 5 GHz Wifi?

Most frames in wifi communication are small, which in turn means that a 40 MHz channel meets the requirements for most types of applications.

My question:

How long has this situation been occurring as the Sonos One HAY speakers have been around for years (not to mention discontinued)? By how long I mean has the issue been occurring ever since they were purchased or within recent weeks? BTW…the internal design of the Sonos One HAY speakers are the same as Sonos Ones without the HAY moniker. HAY is just a color finish. TBH my inclination is that you have network/interference issues.