Can' sign in to iMessage on MacBook M1 with Sonoma...
I've tried everything on the Apple guidelines for this (If you can't sign in to your iMessage account or FaceTime on your Mac – Apple Support (UK) - signed in and out on my iphone successfully, changed my password - restarted my mac... but it just sits spinning trying to sign in to iMessage... the 'sign out' button is displayed, perhaps showing that it thinks it has signed in, but you can't click that either - it doesn't change the sign-in screen.
Any further ideas would be appreciated.
MacBook Air 13″, macOS 14.0