Only works with Ethernet

It isn't that difficult to set up the system, usually. Have you done any investigation into wireless interference in your property?

How often are you changing your router? Everything should be rebooted if you do that.

If the router changes or if a new network is used it is virtually impossible to have SONOS working smoothly.
Why does the router or network keep changing? If you're using the Sonos players on WiFi (aka 'Standard Setup') you'll obviously need to temporarily wire a unit to modify the stored WiFi details when the router/network changes.

I own a pair of Play 1s, but the system only works if one of them is plugged in directly to router via ethernet.

This is the SonosNet ('BOOST Setup') mode, which sets up its own wireless mesh and ignores your WiFi. It's more resilient in general than WiFi mode.

It cannot be this difficult to set up the system. Getting ready to return. Nice sound but very flawed.

It's simple. If you can't figure it out just give Sonos Support a call. They'll straighten you out.

Unbelieveable. I had to create an account just so I could respond to this. I am having the exact same issue. It just started last week. Not sure if there was a firmware update recently? But after working perfectly for the last year my system is screwed. I have two 1's, a bridge, and a 3. My network/firewall settings havn't changed. I connect a 1 to the network so I can setup the "advanced" wireless settings (why you have to connect an ethernet cable to setup wireless is beyond me). Once done it works. BUT! If I now want to disconnect that 1 to move it to another room it completely shuts down the entire network when I unplug it. I've done this multiple times. I've tried connecting and setting up different ways as well.
I consider myself network capable. (no illusions of being an expert) but have setup up and wired our house to multiple systems and media boxes. But for some reason this Sonos has me stumped.

I have run every diagnostic I can on my router and wireless network. No interference. All ports are open. TBH, its driving me freakin crazy.

Unbelieveable. I had to create an account just so I could respond to this.
That's how forums work. You have to create an ID in order to post.

I consider myself network capable.

But you evidently hadn't noticed the difference between SonosNet and WiFi modes.
https://sonos.custhelp.com/app/answers/detail/a_id/3046/~/choosing-between-a-standard-and-boost-setup

You had your system in WiFi (aka 'Standard Setup') mode, which is why wiring a unit to the router flipped it to SonosNet (aka 'BOOST Setup') mode and allowed access to additional Advanced Settings options.

If unwiring a unit -- which flips it back to WiFi mode -- causes trouble then there's either something incorrect in the WiFi details (SSID/key) you entered or something amiss with your router.

Jesus. Thanks for the sarcastic response! Seriously. Gotta love this support.
Yes, I understand the difference.
No, there is nothing wrong with my SSID key or router. You know, I don't care. I can sort it out. Thanks for your "help".

Gotta love this support.
Sonos Support are clearly identified.

We're not Support. We're longstanding Sonos users who provide voluntary assistance. And I'm afraid that coming on the board with a bit of an attitude doesn't endear one much to the community.

That aside, I interpreted "completely shuts down the entire network" as meaning that you lost contact with your Sonos units if you unwired the wired unit. Assuming SSID/key are correct they should reconnect to your WiFi, but you have to give them a couple of minutes to do so.

Noted. Thanks for your help. Apologies for the short response.

Aaah, ratty, I've never been so proud of you, you've made a fat Essex boy very happy!

Starkz, consider yourself lucky, Ratty is the boss dogg round here, fully justified, what he doesn't know isn't worth knowing, so he's worth listening to, unlike myself. If I'd got here first you'd have seen the true power of sarcasm young "Jedi"...

If I'd got here first you'd have seen the true power of sarcasm young "Jedi"...

The sarcasm can definitely get a bit strong around here, but that's part of the charm sometimes as long as it doesn't go too far.

I know we've got two threads going with this same discussion and same posters, so I'll be closing the other one, might as well keep it all in one place. The other thread is here and has some good suggestions from ratty already.

In most cases where the system works well on SonosNet but not on your wireless it's due to problems with that wireless, the network credentials, or the network access devices.

Just to make sure we're all on the same page, when you have a Sonos device wired to the network, your mobile controllers all work fine. You've gone into Wireless Settings and added the network credentials for your network (confirming that they're correct). Then you go to unplug the wired device and all of your Sonos players drop off. From that point, does restarting any of them bring anything up?

If you were to wire the unplugged device back into the network, what other steps do you have to take to bring the units back up? Or do they come on their own after a couple minutes?

If the players will reconnect on their own, can you follow those steps with disconnecting the wire, give the players a couple minutes, then wire it back in if they didn't come on wirelessly, and wait for them to come back up. Once you've got that going, can you submit a diagnostic from your Sonos system and reply back with your confirmation number?

Also, I know you mentioned none of the network settings had changed, do you know if any of your network devices had updated recently? Was there a firmware update for your router that was just installed? What is the model number of the router as well?

Stick with us a bit, the community is a great resource and we'll do what we can to help.

I was as frustrated as some of you, and surprised with the support as some of you too. Found how to fix the problem. Without going step by step in detail what I can say is that once you have your speakers playing while is connected to the local Ethernet (cable) in the Sonos App GoTo Settings > Advanced Settings > Wireless Setup. Took me 4 hours to find out this fixes the issue. I had to do the same for each of the speakers and then all of them were working OK.

EXTRA: Speakers won't start playing immediately, you gotto Group them or select them in the Music section, this is in the main Album / song selection, on the very top of the screen (ROOMS).

Hope this works for everyone. Viva Mexico!