Alexa keeps on saying Sonos One is offline

Further to my Sonos/Alexa adventure - having isolated the problem as originating from my Amazon account having no fixed country or address, I switched to a new login with no such issues, and that seemed to solve the 'offline' problem. However I did have to reset the Sonos One speakers and re-integrate them into the system, and that took several attempts.

The first few times I tried, my old, problematic address appeared automatically as the Alexa account the speakers were registered to. There was an link in the install routine to visit the Sonos Help forums to fix this, but bizarrely that took me to the French language Sonos forums and a page that was missing!

Googling the problem I found the answer was to log out from all the Amazon apps on my phone - music and shopping - because the Sonos install app was taking login info from them (without asking me, obviously.) When I was not logged in to those apps the Sonos install routine gave me the chance to enter the new, fixed, account details. Of course, when i went back to the Amazon app, they tried to log in me in under this new identity, which i did not want, and it took several attempts to stop that happening too.

I now seem to have a fully operating integrated set of Sonos and Alexa speakers. There are only two hitches: when I ask Alexa to play music the Amazon Echo insists on playing it - and though the speaker is good it has nothing on the Sonos One pair. Secondly, my Sonos app now shows two kitchens and two dining rooms, and of course being a Sonos app, there are no easy ways to delete unused or redundant rooms. But frankly those are minor hitches.

Hope this helps anyone jumping through the same hoops.

Had this problem today as i had just moved house
Managed to fix it by goinng to the alexa website and making sure the location and address is correct

need to reauthorize music in the sonos app it will bring you to the alexa app then back to the sonos app.. done its fixed

I have the same issue and Sonos support isn't responding. I want say for now I'm very unsatisfied with the new Sonos One and the Alexa App

so the issue as i encountered recently is that in the alexa app i renamed the sonos from “home theatre” to “living room” — and this was the issue. alexa was looking for a name in sonos that didn’t exist. changing name back to home theater resolved this issue. likely i could change the speaker name in sonos to living room and again in alexa app and it would work that way as well.