Suddenly, this alert pops up on all Roon remotes:
Network is fine, internet connection is up, local content streaming is unaffected. Roon database related activity and Tidal are down.
Some kind of server-side snafu going on?
Update: restarted Roon core and all appears fine again. Must have been a local issue – the red herring was that all cloud activity appeared to be down, while local playback was fine. Oh well…