The ‘ConflictInMappingEntry’ reference means that your Roon Server is using uPnP to request that the router sets up a port forwarding rule to forward port 55002 to the Roon Server but the router already has a rule in place for forwarding port 55002 and so it cannot comply.
This could be caused by another device using the same port - e.g. if you have just migrated your Roon Server from one device to another - or it could be that the Roon Server has been allocated a different IP address on the local network - e.g. if the Roon Server has been powered down for a while..
In either case, the easiest solution is probably to simply change the Roon Arc port number to something else in the range 1025 to 65535 - say 56000.
Alternatively, you may find that simply rebooting your router and the the Roon Server will fix the issue since rebooting the router will clear out all of the previous uPnP created port forwarding rules.
Hello @tgarland, and welcome to the Roon community!
Wade is absolutely spot on with his explanation of the error message. The ConflictInMappingEntry error means that your router already has an active port forwarding rule for the default ARC port, which is preventing your Roon Server from properly configuring the connection.
As Wade suggested, the quickest and easiest fix is usually to change the port number inside Roon. You can do this by navigating to Settings > Roon ARC in your Roon Remote, changing the port number to something else (for example, 55005), and then hitting the “Retry” button.
Please give this a try, and let us know if changing the port (or rebooting your router) helped resolve the issue and successfully connected ARC!
A router reboot will often reset the UPnP rule that Roon and the router firmware negotiate to autoconfigure port forwarding.
If you find yourself frequently needing to reboot the router to resolve this problem, please reach out and we’ll work through some alternatives to autoconfiguration: either a manual rule or Tailscale.
In my post above, I outlined two of the mechanisms by which the “ConflictInMappingEntry” issue can occur. The router reset method of addressing it will only reliably work if the cause was the second reason - the Roon Server ip address changed and the previous port forwarding rule is still in place.
In the case of the first cause of the issue, then resetting the router may fix the issue or it may not. It will essentially be a race between the two devices as to which can establish the port forwarding rule first.
