I’ve been using Sonos/Alexa for years without issue but it is now broken. I cannot set Sonos speakers as the speakers for a group/room in the Alexa app. The error message is
Device not compatible
This device is not compatible with the current selected devices.

This particular Sonos device is a Sonos Amp and was connected fine before. I get the same error for other Alexa/Sonos rooms. I have tried disabling/reenabling the Sonos skill in Alexa. Also added/removed Alexa integration from within Sonos.
How to fix? Thanks.