Hi @getyourcolors.

Welcome, thank you for reaching out to Sonos Community since you already tried some troubleshooting steps let me try to assist you.

Can you try to hardwire the Sonos speaker temporarily using the ethernet cable to your router.

They try to set up the speaker again to the other controller.

You need to set up the speaker wirelessly again Go to Settings » System » Network » Wireless Setup.

Let us know if it works. If you need help with any other information, please be sure to let us know.

Thanks, I don’t have a cable to connect it right now but I’ll try to get it somewhere if thats my only option :)

@Mark P . May I suggest that you re-read the question and reconsider what would be appropriate advice?

@getyourcolors . Please tell us more about your network setup. Just a standard router or a mesh? Any access points, extenders etc?

Is your router dual band 2.4GHz and 5GHz? If so does it have separate network names (SSIDs) for the two bands?

Note also that if your iOS devices are running iOS14 then Sonos requires that in the device's permissions 'Local Network Access ' permission be enabled.

That one I am aware About my network: just one router, nothing fancy. It is dual band but network names are different for each one.

Tommorow I’ll get that cable from a friend btw, so I may try that first advice anyway ^^

Up to you, but there is absolutely no point setting up the speaker again.  Are your controller devices connected to 2.4 of 5 band?  How about the One?

I think the One support only 2,4 bands because it was the only he was able to detect. All other devices both iOS and Windows one are using it too, my 5 band i only for work laptop and house quests.

I checked my sonos account now and even there the speaker appears as online, still works fine with device I was using to set it up. I read that the windows support can be hit or miss but the fact that other iOS devices cannot detect is a real puzzle for me :D

Some routers don't pass data between the two bands and so it is worth checking the speaker and controllers are on the same band.

I would also try powering off router,  speaker and controller devices. Then fully reboot router then speaker then controllers.

I tried rebooting everything yesterday. But now it’s getting even weirder - I powered up my iPad which I don’t use much lately, downloaded Sonos app and… it connected within the seconds, works fine :|

Try 'forgetting' your network and then reconnect. You could try resetting the Sonos app on the troublesome devices too then try to connect to existing system. 

You could try the full works:

Uninstall app

Forget network 

Power off and on

Reconnect to network 

Download app

Connect to existing system 

Btw, the One SL can connect to either band, so it's surprising it could only see the 2.4GHz band. I still wonder if the bands are part of the problem. I have to admit it doesn't look that way though.

If you do wire the speaker that would get rid of that issue anyway.

If your router has 'band steering ' enabled, disable it.

Those steps doesn’t help either. Is wiring the speaker would be only a temporary solution? Because it can’t really be wired all the time, the router is in different room then the one I would like to use the speaker.

To be honest I don’t really expect wiring to help in this situation.  But it may tell us something either way.  The speaker is working and two controllers work fine with it.  I think it would be a pointless and backwards step to set up the speaker again   It must be something on the other devices that is blocking communication, but I can’t think what.

The one thing that temporarily wiring would do is completely eliminate any possibility of it being to do with the two bands - but I think you have more or less done that anyway.

Could you just check one thing - in Settings, System, Network, Networks, what do you have under ‘In Use’ and ‘Other Networks’?

“In use” is my current 2,4h network and I don’t see any other networks there

If your router is broadcasting 5GHz 801.11a/n it should show as an option…. but it is looking increasingly likely that this is a red herring.

Anything in this link that would explain the problem?

https://support.sonos.com/s/article/4875?language=en_US

I don’t think so, all operating systems are up to date. I’m checking the router settings now, can’t find “band steering” yet but I can 100% confirm that router see all the devices (Sonos, iPhones, iPad, TV and my Windows laptop in one network

edit: wireless mode is set to 802.11b+n+g instead of 802.11b/g but I dont think it changes anything

b / g /n is indeed fine