Have you seen this?  A factory reset is not needed.

https://support.sonos.com/en-us/article/connect-sonos-to-a-new-router-or-wi-fi-network

The easiest way to do it is to give your new wifi the same SSID and password as the one it replaces. Otherwise, try this: https://support.sonos.com/en-us/article/connect-sonos-to-a-new-router-or-wi-fi-network

ok - John types faster

It's typical, after I sent my message I fixed it. 

Many thanks for your reply anyway speedy John

I’m not sure about “faster” in this case.  Maybe “less”?  

I have in fact followed @nik9669a ‘s approach for my last two router changes and it has worked like a charm.  Not only does it avoid having to change anything in Sonos, there is no need to change the WiFi credentials in all your other connected devices.

I am not sure that it will work for every router in every circumstance, but it’s definitely worth being the first thing you try.

I also have Play 1 speakers and a Playbar and am having issues with connecting to wifi. When I go to System Settings on the app it shows my system, but when I go to Manage Networks, Update Networks it searches and shows products that I don’t own. It does this even when connected by Ethernet cable.  I asked this question in Sonos community, but didn’t get a response, and I’ve been in touch with Sonos and their answer is to reset. Anyone have an answer without resetting?

Were any of your speakers bought second hand?  If so, then you must reset them.  If you can avoid resetting the original speakers in your system then you need not lose settings anf playlists.

Please give more info on the “history” of your system.

John B, no my speakers are not second hand. Didn’t have any trouble connecting when they were new, but we’ve made a change to our network, and now having problems. I’m able to use them, but have to stay connected with cable. Don’t really want to reset and have to go back and load stations, etc. Besides, I’m curious why this other system is showing up when it searches for mine. They are Era 300, a Beam, and Era 100. Would it pick up a neighbors speakers with BLE, but not mine?

That is pretty weird.  The othr speakers might be discoverable peer-to-peer but I doubt that it is possible for them to join your system as they are on a different network.

I suggest you reset your controller app, but ensure that you opt to connect to existing system, not set up a new system.  Resetting the app loses no information as it is just a remote control for the system.  You will need to enter your Sonos account email address and password.

It is probably unnecessary, but I would consider changing my WiFi password, then allow Sonos to connect by following this guidance:

https://support.sonos.com/en-us/article/connect-sonos-to-a-new-router-or-wi-fi-network

You  can retain all of your system info such as stations etc by leaving just one speaker unreset.  But I don’t think there is any need to reset the speakers

By resetting the controller, you mean signing out or deleting the app or both? 

Have you tried logging on to Sonos.com ? It would be interesting to see what their backend thinks you have speaker wise. One you login, you should see a menu item for System which should show what Sonos thinks you have. 

https://support.sonos.com/en-us/article/reset-the-sonos-app

@Ian_S yes on Sonos.com in System it shows my speakers. It also shows my speakers on the controller app in System Settings, but not when it searches for them under Manage Network. 
I will try the app reset.

Also I’m using the Sonos controller 80.07.03. Not the S1 controller. If this makes any difference.

Was your system previously working or have you also changed something like WiFi or added new Sonos speakers or reset any speakers? 

Yes previously working on WiFi. SSID and password were changed. That’s when I wasn’t able to connect back to wireless WiFi. Nothing else has changed. I reset the Sonos controller app on my iPad, and no change. Still shows other speakers, but not mine.

If you’ve changed WiFi SSID and/or password then you have to reset the Play:1’s and the playbar… they have no Bluetooth LE to allow the app to connect and change it. See here…

https://support.sonos.com/en-gb/article/connect-sonos-to-a-new-router-or-wi-fi-network

All your products are unfortunately in the unsupported category…

That’s what I figure, but they say you can reconnect them to WiFi with an Ethernet cable. Help desk couldn’t understand why they wouldn’t so they just throw up their hands. I’m going to wait until we change our router before resetting, and if we decide to change WiFi providers I’m sure I’ll have to go through it again. 

Are the Play:1’s surrounds for the play bar?

Two of them are

The surrounds can’t be connected via ethernet to change anything as they use a special bonded wireless connection to the playbar. The only way is a reset and re-add. If plugging in the playbar via ethernet doesn’t allow you to change the WiFi settings then unfortunately it’s a reset too.

The thing to look out for if you have to reset the whole system is whether you have any Sonos playlists. These will be lost I believe, although there are some tools that can extract them. Others here may be able to help more on that. 

If you change router for a new provider, by far the easiest way to do that is to change the new router to have the same SSID/password combination as the old one. Then just reboot everything. Saves a LOT of hassle. 

Thanks Ian_S, but not sure if I had known all of this before whether it would make things easier. Am I the only one who thinks connecting Sonos speakers to WiFi is extremely difficult? I had to reconnect all of our “smart devices” which is a pain, but not as much trouble as this.