What router (Make/Model) and controller device (OS) are you using? Can you also perhaps kindly confirm you are using the S2 Sonos App (gold icon), rather than the S1 Sonos App (black icon).

I am using the S2 app , a BT home hub router and an IPhone 12 , I have also tried an ipad

An update to the BT smart hub 2 router is mentioned in some threads here in the community, which is causing isolation problems. Users say switching off its 5Ghz radio solved their problem, so perhaps give that a try to begin with.

It seems the 5ghz band is being isolated from the 2.4ghz band due to its firmware and some users have reported the issue to their ISP support desk. 

Thanks for that , the other sonos products on the network connect and work fine and it does detect the Roam it just won’t register it, wouldn’t it just not find it if that was the issue

Yes, I see your point, but perhaps just try switching off the 5ghz radio temporarily. Reboot the speaker and close/reopen the Sonos App and ensure your mobile is connected to the 2.4ghz band and then try the registration. You can then turn the radio back on again afterwards. Nothing ventured etc… 

If still no joy, then also try switching off the iOS ‘Private Address’ MAC spoofing features in your iPhones network connection properties.

Hello,

I'm having this exact problem myself. Have a number of other Sonos products connected to my network, but the Roam keeps getting an error message and doesn’t seem to be able to register on my Sonos App.

I’m not techy (part of Sonos appeal is it’s simplicity) so asking about 5G radio waves is beyond me I’m afraid. Should work out of the box should it? What was the final solution here please?

Thanks.

Same issue here.  Connects to network but won’t register. It shouldn’t be this difficult.