· Do you have a mesh network? (Google Mesh, Eeros, Ubiquiti, etc.)
ARC Status
· ARC is *Not Ready*
Roon Error Code
· None of these are listed. It simply says "TIMEDOUT" or similar.
System or third-party *firewalls *or *antivirus software* can sometimes block RoonServer from reaching ARC.
· Try adding RoonServer and its associated processes to the whitelist of any firewalls or antivirus software you have installed, including the Windows system firewall, if applicable. [You can learn more about firewall exceptions with Roon here.](https://help.roonlabs.com/portal/en/kb/articles/firewall)
Has the status in Roon -> Settings -> ARC changed after adding exceptions in your firewalls and antivirus software for Roon? I don't have any system or third-party firewalls or antivirus software.
Have you successfully located and enabled the UPnP or NAT-PMP settings in your router's web UI?
· I've turned UPnP/ NAT-PMP on and ARC won't connect
Select the Diagnostic Keyword or Text String
· Something else
Don't give up yet.
· I'm stuck. I'd like to create a post to ask Roon Community for help.
Thank you for working through the steps before posting. Your setup tells us most of what we need, and the likely cause is not the firewall or UPnP.
You have a Virgin Media hub and a TP-Link Deco X75 Pro mesh. Unless the Virgin hub has been changed, that means there are two routers in series, each performing its own network address translation. UPnP on the Deco can only open a port on the Deco. It cannot open one on the Virgin hub in front of it, so the connection from outside still stops there. That is why turning UPnP on made no difference, and it produces exactly the 504 you are seeing.
The clean fix is to remove one of the two layers. Please put the Virgin hub into Modem Mode, so that it acts only as a modem and the Deco handles your network. Virgin documents this in their own support pages and in the Connect app, and it is reversible. Once the Deco is the only router, its UPnP can do its job.
If you would rather keep both, then a port has to be opened on both. Create a manual port forwarding rule on the Deco for the port shown in Roon → Settings → ARC, and then add a matching rule on the Virgin hub pointing at the Deco.
Other people with the same combination have posted what worked for them here, and it is worth a look:
One thing to rule out before you spend time on any of this. Some accounts are placed behind the provider’s own network, in which case no port forwarding on your equipment can work. Please compare the internet address shown in your Virgin hub with the one Roon reports in the ARC diagnostics. If they differ, that is what is happening, and the question for Virgin is whether they can give you a public address instead.
What would help us:
Please paste the full text from Roon → Settings → ARC, the whole block that begins { “ipv4_connectivity”…, rather than just the error number. It tells us which stage is failing.
Is the Virgin hub currently in Modem Mode, or is it still routing?
Is the Deco set to Router mode or Access Point mode?
Any other network hardware between them, such as a switch or a second Deco acting as a router?
Wanted to follow up on this. Have you had a chance to put the Virgin hub into Modem Mode, or, if you prefer to keep both devices routing, add matching manual port forwards on both the Deco and the Virgin hub for the port shown in Roon → Settings → ARC? It would also help to confirm whether the Virgin hub is still routing, whether the Deco is in Router or Access Point mode, and to paste the full ARC diagnostics block so we can see which stage is failing.
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