We’re sorry to hear you’ve suddenly lost connectivity. Be advised we are just resolving a broader server issue - you can view the current status here: ARC Poor Connection / ARC Unable to Connect to Core [Investigating]
The diagnostic you’ve provided, however, suggests that UPnP has been misconfigured in the router, or the UPnP protocol is otherwise failing to properly configure the port/IP in the router. Often, this is a result of a router firmware update (or required update), DHCP certificate renewal, or other backend change in the router settings, and can be easily resolved with a restart of your network hardware.
I’d toggle UPnP on/off in your router web administration just to be sure. If that fails, you can try setting a manual port forwarding rule using the port number and Core IP from Roon → Settings → Roon ARC.
We’ll keep a lookout for your response.