When you open the Sonos App on a new WiFi network you should be seeing this screen… maybe try fully closing the App (slide off screen), wait a few seconds and open & try again.

The message now is “We can’t find a Sonus System on <name of my new WiFi Network>

Make sure your Sonos system is powered on and connected to network….

Hmmm… the Arc is white light the other Arc is white light - what am I missing?

It won’t find the system on the new network you need to add your products to the new network - maybe see the instructions here, provided by Sonos:

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

Obviously, ensure your mobile controller device is connected to the new WiFi Network too.

Setup any devices you have with .BLE support (Beam, Era 100 etc. or try wiring your product to the local router). Once you have the majority setup and running, if you do encounter and stubborn products you can reset/add those back manually, but only ever do that when your system is backup and running and showing in the Sonos App.

If you give me a moment I’ll go through the process here and maybe post a few screenshots that may perhaps assist you further.

So if you go onto select update network then you should see the following screens (I’ve just put them together quickly below) - select your .BLE or wired product and update their settings… I hope that helps. If your problems persist, then maybe try a router, mobile-device and speaker reboot and try again.

Many thanks the app is a bit glitchy but I got 2 completed.

I’ll start a new thread as I think it is a different issue the Sub keeps falling out so I'll start another sting even after a Factory Reboot multiple oh well ;-)

I cannot get ‘Update Network’ to appear anywhere in the app. I’ve tried logging out/in, I’ve tried deleting the app. Nothing I do seems to be able to show this screen. Is there any way I can manually prompt it? This is kinda driving me nuts. We’re just on vacation and want to use the Roam in the Airbnb. 

The Airbnb may have some network controls installed for guest access that will frustrate a SONOS system. Personally, I would bring a travel router to an Airbnb.

A quickie, temporary workaround might be to Bluetooth to ROAM.

It should show when you’re not in range of any previous WiFi network and the product in the Household is not already on the new WiFi network (obviously) - maybe the attached screen-capture recording will perhaps assist you. 

I don’t get this screen. System settings doesn’t have anything about updating the network. 
 

I ended up doing a factory reset on the Roam to get it working, but it seems insane to do this. The Roam is supposed to roam!

Problem solved for now, and maybe most people don’t take their Sonos devices to new locations, but this seems like an obvious use case for a portable speaker.

You likely won’t get the screen mentioned, if you’ve factory reset the product, or if you reset the App aswell, as it goes onto scan your account for the product to then add the WiFi network/credentials to the ’existing’ Sonos Household. If you factory reset the speaker, you ‘likely’ also need to create a ‘new’ Sonos Household to hold that speaker by resetting the Sonos App aswell… that’s unless you have a Sonos Household already on the network. (You will always need a Sonos Household/System to ‘house’ (hold) your speakers).

I didn’t get the ‘update network’ screen before factory resetting or deleting the app.

After I deleted the app I logged back in, which showed nothing. 

If doing the above removes all state and then doesn’t allow me to adjust any network, Sonos’ assumptions about standard troubleshooting are strange. 

I should be able to take my Roam wherever and easily update the WiFi without any pain. Having the “household” or “system” explicitly tied to a network id is very strange imo. It should be able to exist apart from it and have the id updated without hassle.

It does, but it seems you ‘may have’ taken a wrong step somewhere along the way - it’s perhaps a bit late now, but I would have suggested to you to simply log out/in on the Sonos App and/or reboot things, rather than ever resetting the controller (or the Sonos product). Once you reset the last available Sonos product you then lose access to the Sonos Household.

You can add up-to 16 WiFi networks to the same Sonos Household. It lists the WiFi Network SSID’s in the controllers Network Settings area.

I have the exact same problem, and apart from resetting speaker (Move 2) every time I take speaker to a friend's or on the job (every day), there's no way to add all the wifi networks it's supposed to be able to have be cause ‘update network settings’ is nowhere to be found on app. 
The original Move and S2 app didn't have this problem. Very frustrating. 
Sonos acts like they have no idea...

Well it should be working, but don’t reset your Sonos product or your Sonos App. There's no need to reset anything… the WiFi networks are added to the Apps network list. See example screenshot…