Hey Sonos engineering, you know what? How about putting the version numbers in this error message? ie the version of the app, and the version of the device that doesn’t match. And, gravy, the name of the device?

This is another example of when a simple engineering change would make helping people (both us volunteers and your paid Support teams) easier for common cases.

(An aside: does anyone know what the “not registered” message is all about?)

Back to the problem at hand, no thanks to Sonos Engineering:

Are you running the S1 or the S2 app?

Are your devices running S1 or S2? (Or were they anyway, could someone have upgraded them ‘accidentally’ recently?)

Both on S2

Moderator Note: Recorded and removed Serial Numbers. Modified in accordance with the Community Code of Conduct.

I’d start with making sure your controller and the Play 5 are up to date on their software.

Once that is done try powering the One down and back up. If that doesn’t get it try hooking it to Ethernet temporarily.

Well those devices are both current S2, what is the version of the app that is complaining?