Hi @Philip C,

Thanks for sharing your solution!

We have a fairly popular thread on this topic already, where some users have found similar success in downgrading the firmware on their routers to regain connection. Other people have found success in simply factory resetting their Asus router after an upgrade, which is the solution sometimes offered by Asus support. 

Regardless, I’m glad you were able to get connected again. 

I ran in to a similar issue with my pair of Sonos One with the Asus Zen WiFi AX Mini XD4 Mesh system with firmware 3.0.0.4.386.45934

My Sonos One speakers would not communicate or re-join the wifi network until I downgraded the firmware back to 3.0.0.4.386.43129 (which was the last version prior for this system) -- on that system, I was able to just use the web interface to downgrade each of the nodes.

My SONOS One speaker system suddenly today refused to connect to my ASUS rt-ax58u wifi router. Everything has been working fine for more than one year.

The ASUS formware (version 3.0.0.4.386.45898) was last updated about three months ago (2021/10/07) so that cannot be the culprit here. I have not done any changes in router settings or speaker settings. I have tried resetting the router to factory settings and then updating its firmware and settings again, but without any success. My problem with the SONOS system therefore remains.

SONOS support people blames ASUS (of course), but I have my serious doubts since the router firmware hasn’t been updated lately.

Nor, for that matter, has the Sonos software. Which suggests a change in the local environment of some type. Have you tried submitting a diagnostic, and calling in to discuss it?

@Airgetlam Yes, I have contacted them, and spent about half an hour with them. All they said was that the SONOS engineers had concluded that it was a problem of ASUS.

The problem is quite strange but entirely outside my skills or interests to spend time on fixing. None of my other wifi devices have been affected. I will therefore sit tight for a maximum of 7 days. If no solution pops up within that period I will scrap the SONOS speakers and never look at that brand again — like most consumers would.

I now rolled back the ASUS firmware to version 3.0.0.4.386.45674 from 2021/09/22. But the problem with the SONOS speakers still remain. More and more symptoms point to SONOS as the culprit — contrary to what they claim themselves.

What symptoms lead you to this conclusion and how?

In this thread link:

https://en.community.sonos.com/troubleshooting-228999/new-asus-rt-ax82u-ax5400-router-sonos-system-not-showing-any-recommendations-6852148?postid=16495713#post16495713

…the users who rolled back their firmware to these versions:

• Version 3.0.0.4.384.10177 (dated 2020/11/26)
• Version 3.0.0.4.384.9948 (dated 2020/11/03)

… got Sonos working on their Asus routers and then more recently in this thread:

https://en.community.sonos.com/troubleshooting-228999/new-asus-rt-ax82u-ax5400-router-sonos-system-not-showing-any-recommendations-6852148?postid=16558963#post16558963

…the user bruvva74 managed to get Sonos running on his Asus router, in wired SonosNet mode with the ‘latest’ Asus firmware update. (Not sure what firmware version that was used here, but it appears to be the latest release?) 

So maybe contact the Asus router users in these threads to see if they can kindly assist you to get your system up and running or maybe try the firmware version they mention.

Followed all (new) steps above: rolled back ASUS firmware to 2.5 year old versions + factory reset the ASUS router etc. No success.

Of course, wired Sonos mode works. But that’s because it uses the ethernet cable then, and not the wifi at all. As soon as the ethernet cable is unplugged the SONOS system stops working. So this is absolutely no solution, or even a work-around. This is also obvious from carefully reading the discussions in the last link supplied by @Ken_Griffiths above.

In Ken’s first link the discussion is more than 1 year old, and it is about installing a totally new router. My situation is (as mentioned above) totally different. My system has worked well for a about a year, but now suddenly stopped — although I hadn’t changed a single thing (router or speakers).

One thing I noticed is that after factory resetting the SONOS speakers they still remember a few settings, such as system pairing. These settings still persisted even after I reset the SONOS app and then logged back in to my account. Conclusion: The SONOS factory reset process cannot be trusted, at least not together with their app.

Exactly how are you completing a factory reset on your speakers? Just unplugging then plugging back in?

If so then follow these instructions instead to Reset your Sonos product

Not once have I experienced a factory reset speaker remembering previous settings.

I performed the factory reset exactly as in the link you supplied, @Mr. T  Unplugged power cable, replugged it while keeping the speaker’s connect button pressed etc. And the speakers and Sonos app responded correctly to the factory reset too.

I didn’t notice that some settings were kept at first either. But later, when I was connecting one of the speakers with ethernet cable directly to the wifi router (right after factory resetting that speaker), the Sonos app told me that the speaker belonged to a system of two and had to be uncoupled before proceeding. There is no way that coupling could have happened by itself, because the other speaker was entirely powered down (and unplugged), and the Sonos app had been reset (but then logged back into my account). So either Sonos is saving some settings in my account data or in the speaker — even across factory resets.

Please read:

Previously I had downgraded my firmware as couldn’t get my RT-AX82U to see my speakers at all. However, due to other non Sonos related issues I needed to upgrade to the latest firmware version.

I updated to 3.0.0.4.386_46061 last night and at first couldn’t see my speakers but after a bit of tinkering all is working as intended.

My setup is just two speakers both connecting directly to the router via wi-fi

Steps I took:

1. Updated firmware through router UI
2. Reset router through UI - Administration/Restore tab - Factory reset with Initialize ticked
3. Uninstalled Sonos controller from PC and Sonos app from phone
4. Reset speakers as per the official guide
5. Reinstalled app on phone
6. Setup new system on a single speaker via mobile app
7. Reinstalled controller on PC
8. Added additional speakers through app

I tried numerous ways off getting connected to my existing system after step 2 but nothing I tried worked.