Have you tried temporarily cable connecting one of your speakers?

yes I also did that but after that it seems impossible to connect the speakers to the wifi again, and due to the placement of my router I can’t leave one plugged in permanently 

Can you put in the wifi credentials while the system is cable connected?

If not, maybe you could elaborate on your wifi set up?

I have the exact same issue -  can’t get past the screen below.

I now have the same problem.

I have a Symfonisk gen1 (I purchased it several years ago). It used to work fine. Then over the past few months it started to become flaky. I could not get it to connect to WiFi. After making some changes to my router to limit it to 2.4G (in case that was the problem) it still would not connect. 

So I decided to try full factory reset and I deleted and reinstalled Sonos S2 app on my phone. Now I can’t get past this Accessory setup phase.

I’d say after the Factory Reset your best chance is contacting Sonos support.

The reset is usually a bad idea and can be difficult to recover from as all your original settings are erased.

I too am stuck at “Accessory Setup”.

Sonos Play 5 gen2

iOS 17.2 beta

Eero mesh network running eeroOS v7.1.0-3704

Everything has been rebooted, factory reset, deleted and reinstalled, all to no avail. 
 

Dead in the water at this point. Might try Ethernet next. 

Note it might be the fact you’re using iOS beta software as that OS is not officially supported by Sonos and so some things may not work until it’s been generally released to all by Apple. If you have another iOS device that’s running iOS 17.1.2 then maybe give that a try.

Same issue here. My setup had been working fine up until 2 days ago and the app would keep telling me it couldn’t find my Sonos system, yet I could tell my Echo to play music through them. 

2x Play:1

iOS 17.1.2

Unifi WAP

I’ve been using these for years on the same wifi, so it’s pretty annoying that they suddenly drop off the face of the planet.
 

Must be a different issue as you’re not using beta iOS software. In your case it sounds like a multicast discovery issue by the iOS device. I would update it to iOS 17.2 and then check for Sonos updates. If the issue persists then check any security apps on the iOS device such as VPN client etc. Maybe switch off WiFi calling and the Sonos App acces to mobile data and perhaps even see what happens if you disable private WiFi address in the iOS network connection.

What might also assist you is to reserve your Sonos IP addresses in your routers DHCP reservation table and ensure both speakers and phone are using the same WiFi AP.

A combination of rebooting my iPhone, and renaming the Play:1 when trying to set it up looks to have overcome the unexpected error issue. I had to set it up as a new system. 

As long as you’re sorted and happy then that’s fine. Some of the things mentioned though, like reserving the Sonos IP addresses in the routers DHCP reservation table may have sorted things for you anyway and it could also help to reduce the risk of such things happening in the future too, I suspect.