It sounds like you may need to speak to Sonos support if you can’t access them. Have you perhaps first tried powering off your router and Sonos devices and bringing each of them back online in this order:

• Modem/Router
• Wired Sonos Products (nearest device to router first)
• Wireless Sonos Products  (nearest device to router first)

*Allow each device to settle for a minute or so and connect online before powering on the next device.

Try that first and if still no joy contact Sonos Support here:

https://support.sonos.com/s/

Dear Ken, thank you very much for your kind and prompt reply! The thing is that I downloaded Sonos 2 controller and then updated my sonos products. it turns out they’re too old for the new technology. So I’m trying to get back to my old technology (sonos S1 controller) but now neither airbridge nor two of the speakers will work. I want to undo the update of these products (airbridge and 2 speakers) 

And when I get into that link I can’t find an email to email my issue to. 

Can you perhaps kindly clarify what sonos products you have and I will see if I can try to assist you.

There is a ‘live-chat’ option, but not to worry you can look at that later. It should be easy to resolve this once you state which products you have.

You are too kind. The products that I’ve hastily updated and now won’t work are these: 

BRIDGEhijvt

Version: 11.2.3 (build 57381090) (I don’t know if this is the new version or the old one but i suspect the new one)

Hardware Version: 1.5.0.0-2.0

Play:5:

Version: 11.2.3 (build 57381090) (I don’t know if this is the new version or the old one but i suspect the new one)

Hardware Version: 1.16.4.1-2.0

I guess it’s just that the hardware is really old. I think I’ve had this bridge and speakers since 2004 or something. Updating them was a mistake. 

Although weirdly I’ve just found out that I can use them in Sonos 2 but not the original Sonos S1. Weird.

 So at the mo I can play some of my speakers with one app and the other with another…. 

Thank you very much for you kind concern xxxxx

Firstly the Sonos Bridge cannot be updated to the S2 system - it’s S1 only. I assume your Play:5 is a 1st generation Play:5 (is that correct?) as it too is showing as being on the S1 System.

The Play:5 gen1 looks like this and has sonos logo at foot of speaker:

Anyhow perhaps try this - remove the (gold) S2 App if you have that installed and reset the S1 App and on re-opening the S1 App choose the option to connect to the ‘existing system’ (do not create a new system).. and see if that sorts things for you.

Dear Ken, 

You’re very kind to have gone to all this trouble for me. Thank you so much for your kindness.

Yes, indeed that is one of the speakers that doesn’t work. And the other one is smaller but exactly the same “generation”. They were bought at the same time what seems like a century ago.

I might do what you are suggesting. Although currently it’s all working on two separate systems. So, given the amount of other stuff going on right now I may just leave it as is for now and do what you suggest as soon as I can. I fear it may all just stop working which given other stuff going on right now would be a disaster.

again, I’m immensely grateful for your kind assistance. thank you a thousand times over xxxxx

That’s okay Tigerlilly, anytime and if you do ever decide you want to revert back to a S1 (single household) system only, then let me know and I will try to assist… in simple terms though, I will describe the basic steps of what you need to do here in case you ever decide to give it a go on your own.

1. Uninstall, or set-aside, the (gold) S2 Sonos App and power off all Sonos devices before starting.
2. Cable the ‘currently working’ Sonos Bridge (if using) to the main router and any single older Sonos Speaker, either to the Bridge (preferred), or to the router itself. Power them on (Bridge first, ideally) and ensure both the Bridge and speaker appear in the (black) S1 Sonos App and that both are working correctly. Also check all devices are up-to-date.
3. If you cannot get the Bridge and/or a single Sonos speaker to appear, or work correctly, in the S1 App, then Stop there and seek help from the Sonos community here, or contact Sonos Customer Care. 
4. Next, switch on any older remaining S1 unwired devices that had recently been seen/working okay in the S1 App and ensure they too connect to the S1 Household and check they are also working correctly - if they do not appear after one or two attempts of powering them on, then go onto next step.
5. Factory reset any speaker that does not work ‘correctly’ or does appear in the S1 App. This will include resetting those Sonos devices that had been upgraded to S2 and were working in the S2 Sonos App ...and then use the ‘Add Product’ option (in the S1 App "Settings/System”) to add the reset speaker/device back to the S1 System - this will forcibly downgrade the S2 speakers etc; back to the S1 firmware and each will then work within the S1 App. 
6. Once all devices are done and everything is working okay, you can un-cable any speakers (not the Sonos Bridge) from the router.  You can also uninstall the S2 App (if not removed earlier) as it’s no longer required. Everything should then run in the S1 system only.
7. Note (just for info. only) some devices like Sonos Arc, Sonos Five (gen3) and Sub (gen3) cannot be downgraded to S1 and are S2 compatible-only products. 

Hope the above information proves to be helpful to you too.

Beware: going back to S1 did not work for me with a One recently, and I tried everything. YMMV.

The important bit (at least, at this moment in time) is that to actually downgrade a ‘compatible’ Sonos device to S1, you must first have an ‘existing’ S1 Household already setup & running to add the device to, for it to then be forcibly downgraded.
 

Without an existing S1 Household, you would either need an S1-only ‘old’ Sonos device to create such a Household to start with, otherwise (quite possibly) you may (just ‘may’) require the help of Sonos Customer Care to ‘perhaps’ resolve the matter… I’m not sure about the latter option however, as I have not heard of anyone going via that route at the moment.
 

I think many will just probably stick with their S2 setup ...er...once ‘the bridge’ has been crossed.

Like I said, this did not work for me. I had a Symphonisk on S1 and could not take a One back to S1 after having upgraded it (elsewhere) to S2. There is a thread somewhere on my travails.

Strange controlav, I can’t say that I have a symfonisk device to test that particular scenario, but I have certainly (and recently) upgraded and downgraded several Play:1 speakers here, but my existing S1 HH consists of a Bridge and at least one Play:1 Speaker that I chose to keep separate on S1 to my main S2 Household. 

I do expect the Sonos policy to perhaps change on downgrading eventually, but there has to be a route for those users who which to sell S1/S2 compatible, but upgraded, devices onto those users who only have an S1 Household - at least for a certain period of time.

You’d need to temporarily remove the S2 app from your mobile device, apparantly it’s messing with the downgrade process.