Solving the double NAT error?

Roon Core Machine

iMac 2017
Monterey 12.6
4.2GHz Quad core Intel Core i7
64GB 2667 MHz DDR4

Networking Gear & Setup Details

VDSL connection => Archer A9 gateway (NAT configured) => Ethernet connected to a second A9 gateway set as Access Point (no NAT) => ethernet connection to roon core iMac

Connected Audio Devices

Ethenet connection from roon core iMac to Cambrdige CXN2 V2 => Naim 5si and Rega RS3s

Number of Tracks in Library

<500 as I mainly use Tidal to stream

Description of Issue

In concept my network is running a single NAT as second gateway set as access point. but getting this error:

“connectivity”: {“status”:“NetworkTimeout”,“status_code”:998,“error”:“”},
“external_ip”: {“actual_external_ip”:“203.211.x.x”,“router_external_ip”:“”},
“status”: “status”: MultipleNatFound
“natpmp_autoconfig”: {“status”:“NotFound”},
“upnp_autoconfig”: {“server_ip”:“”,“found_upnp”:true}

I’m no networking specialist - can somehow help me get Arc setup? Possibly need to setup port forwarding, but need some support! thanks in advance

Your network has more than one router, so multiple NAT is reported. You’ll need to follow the instructions in the guide below.

It would seem that you have two networks: and The latter appears to have UPnP set up. Therefore, manual port forwarding is needed in the first router.

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This address probably means your ISP uses CGNAT. You’ll need to talk to them about getting around that or try the Tailscale VPN workaround.

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HI @Luke_Concannon,

It looks like you’ve gotten some guidance on how to continue. Here’s our form response for this issue with some things to consider.

Thank you for your patience while we’ve diligently worked to reach every request for support with port forwarding. The diagnostics you’ve provided suggest that your Core is having difficulty reaching our servers. There are several independent factors that can cause this error, so we recommend double-checking the following to initiate troubleshooting:

  • Is your router firmware up to date?
  • Do you have any VPNs, proxy servers, or enterprise-grade security on this network?
  • Are you experiencing any issues with Roon Remotes, or other apps on your local network?

If you continue to experience difficulties, please tag the support team and include the following information:

  1. What is the make and model of your modem and router?
  2. Do you have any additional network hardware, like additional routers or managed switches?
  3. Who is your internet service provider and what is your geographic region?
  4. Is your Modem configured in Bridge Mode so that it operates only as a modem or do you have the ports forwarded on both?

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