Thank you for the post. There was a backend issue that has since been resolved - please restart your RoonServer and resync ARC over WiFi.
Are you seeing any other errors at present in the ARC UI, like an ‘unauthorized’ banner message?
If so, you might need to reinstall the app as a temporary workaround to reassociate the session layer with your current RoonServer. We have work in progress that should prevent you from having to take this reinstall step when this session dissociation occurs, but we haven’t yet released those improvements.
Our apologies for the inconvenience. Please let us know if this helps.