Something is going horribly wrong with your network. Such factory resets should never be necessary for what appear to be ‘simple’ connectivity failures. (In ~14 years I’ve never had to reset everything.)

I infer from your comments that the system is in “wireless”/WiFi mode, i.e. without a Sonos component wired anywhere. What make/model is the router? 

Have you tried consulting Sonos Support after submitting a diagnostic?

Indeed, have you tried wiring a Sonos component and operating in “wired”/SonosNet mode?

Funny thing is everything else (over Wi-Fi) works exceptionally well. I have a 600/100 connection which is more than adequate for general purpose. 

Yes, all my units are connected wirelessly. I had no issues with my previous Asus router, but since I moved and since I had a new ISP that forced me on their own bullshit router what I think is a Sagemcom FAST3890V3, I started having these issues. I could potentially bridge their shitty router with my own, but then I’m dealing with yet another unit to track… So if I can find the root cause and rectify the issue I’d prefer that over adding my other router.

I actually consulted with Sonos Support a while back after the fact I had my first encounter with this issue, and at the time, probably because of the connectivity issue itself, I couldn’t send a diagnostic log unfortunately.

I’ve not tried that, not even sure what that feature is. You mean to use one of the units as a wired applifier of some kind. If I connect 1 units over ethernet, would that in turn transmit wirelessly to the rest of my units?

Just out of curiosity, do I need to be on the 2.4 ghz network to manage and steer my Sonos app or is it intelligent enough to route my traffic accordingly if I’m on the 5 ghz network?

With a decent router it won’t matter which band your Sonos is on, nor which band your phone is on. However some uncooperative routers don’t consistently forward the necessary local traffic types between segments, hence the controller is unable to discover the players. 

If you can manage it, I’d suggest running an Ethernet cable to one of your players and see how well that works. You only need wire one device, as Sonos deals with the communication between devices. Note that you should not choose a home theatre surround speaker or Sub as the sole wired device.

After connecting the cable wait 5 mins for the system to reconfigure itself onto SonosNet. In the Sonos app’s Settings>System>About you should then see all the units showing WM:0.

Alright, according to my ISP this is supposedly a high-performing router and judging from its specs it’s actually alright. Not the best one out there but definitely not the worst. I’m puzzled as everything else works flawlessly… It’s just my Sonos setup that harasses me for some reason.

I have my setup organized as follows: 2x Sonos One in stereo + another 2x Sonos One in stereo and the beam is for my TV. No surround setup is configured. All Sonos Ones are mounted in each corner for a 500 square feet, open room so there should be minimum interference in general. 

Easiest for me is to run a cable (for the sake of testing) from my router to my beam. I don’t one long enough at this point but will surely get one. No manual intervention apart from connecting the ethernet cable is needed to setup SonosNet?

Lastly, what purpose does SonosNet serve? What are we actualyl testing here?

Probably everything else just wants a connection to the internet. Sonos is a complex system that also depends on reliable connectivity between devices. 

Correct. After a bit of flashing of LEDs the units should switch themselves over to using the SonosNet mesh. 

A SonosNet system appears to the router as wired, including all the Sonos devices which are wireless since they all connect back through the wired device. If that all works consistently it would support the theory that the router is somehow impeding local traffic between its WiFi segments.

BTW if running a cable to the Beam is less than convenient longer term there is always the Sonos Boost. That’s what it’s for.

No inconvenience at all I actually have a canalization prepared for it, I’m just a no-cable guy. I’m going to take your advice. I appreciate the help!

Another observation I did just now is while I’m attempting Spotify playback via Sonos app, Airplay works perfectly fine. Any thoughts?

It’s possibly because Sonos and Airplay use different discovery protocols.