Xfinity ISP, Model CGM4331COM (modem/router); connection via coax from street to modem, ethernet from modem/router to PC and Nucleus One. The Roon Server information has a MAC address, a IPV6 address and a IPV4 address. Roon is running on a Windows 11 Home, version 25H2, build 26200.9168. ARC worked fine via Wireless to my car and phone up until this last update of yours. Then it tried to stay connected but failed after several minutes of play and now it doesn't connect at all.
One thing first, because it shapes the rest. A Roon update does not change your router, your network or any port forwarding. What an update can do is coincide with your server being given a different local address when it restarts, and if a port was forwarded to the old address then that forward stops working. So the timing you noticed is real, even though the update is not the cause.
The diagnostics you provided suggest that UPnP is not properly configured on your router. Roon looked for a router that could open a port for it and found none, which is why both connection tests return the 504.
Please first try the following steps:
Try to enable UPnP/NAT-PMP in the web administration interface for the router directly upstream from your Roon Server
Try to manually open the port in your router’s port forwarding configuration
Make sure the IP and port match the port listed in Roon → Settings → ARC
Check for any VPNs or firewalls that might be interfering
Check whether your modem is in Bridge mode
On the form you told us you use your ISP’s router alongside a personal router, so one further point applies. Two routers in series create a second layer of address translation, and a port then has to be opened on both of them or ARC cannot work. If that is your setup, you have two choices:
In the Xfinity gateway’s administration interface, enable Bridge Mode, so that it acts only as a modem and your own router handles the network.
Or, if you already have a port forwarding rule in your own router, add a matching rule on the Xfinity gateway so the port passes through both.
If you continue to have difficulty, please reply here with the following:
What is the make and model of your modem and router?
Do you have any additional network hardware, such as additional routers or managed switches?
Who is your internet service provider and what is your geographic region?
Is your modem configured in Bridge Mode so that it operates only as a modem, or do you have the ports forwarded on both?
Just checking in on this. Were you able to try the UPnP or NAT-PMP setting on the router directly upstream from your Roon Server, or set up a manual port forward that matches the port shown in Roon → Settings → ARC? Since you mentioned using your ISP’s router with a personal router, we also wanted to ask whether the Xfinity gateway is in Bridge Mode, or whether the same port has been forwarded on both devices. If you have a moment, send us an update on what you found and we can take it from there.
Please note, if we don’t hear back from you this thread may close automatically soon. If the thread auto-closes and you need further assistance, please submit a reopen support request via the technical support help form below and specify that the issue should be reopened. Thank you.