Roon Arc cannot access my Roon Core

Roon Core Machine

ROCK on NUC Barebone BKNUC8V5PNH Core i5-8365U 16GB

Networking Gear & Setup Details

Netgear R6850
NUC connected via ethernet RJ45
All Sonos Devices WIFI

Connected Audio Devices

1 Sonos Port
1 Sonos Move
1 Pair Sonos One
1 Sonos Play 1 Gen 2
All connected via Wifi

Number of Tracks in Library


Description of Issue

I get following error message
“connectivity”: {“status”:“NetworkError”,“status_code”:504,“error”:“error: Error: ETIMEDOUT, response code: undefined, body: undefined connected? undefined”},
“external_ip”: {“actual_external_ip”:“”,“router_external_ip”:“”},
“status”: “status”: MultipleNatFound
“natpmp_autoconfig”: {“status”:“NotFound”},
“upnp_autoconfig”: {“server_ip”:“”,“found_upnp”:true}

Thanks for your support.

Which country are you in and what ISP do you have

Switzerland and ISP is UPC-Cablecom

Hey @Jean-Claude_Mounir,

I wanted to check in on this thread to see if you were still having issues setting up arc? After reviewing your error code, it looks like you may have an issue with multiple Nats set up in your network configuration.

If possible, are you able to provide more information and details about your full network setup, with the specific router and modem models?

If you haven’t yet:

  1. Put all but one of your routers into bridge mode.
  2. Manually set up port forwarding on each router pointed towards your Core until you get to the router that the Core is plugged into.

Here is more info on this :

I’ll be monitoring this thread for your reply :pray:

Yes I still have the same issue.
My router model is a Netgear R6850.
As I am not at all at ease with such technical questions, can you please be more precise about what you like like to have about my router settings.
Thanks for your help in this matter.

Hey @Jean-Claude_Mounir,

Were you able to give the help article above a read? It will definitely help you better understand what settings you may have to adjust on your router to get Arc up and running.

After giving that a read, I’ve found specific instructions for your router on how to get port forwarding setup:

  1. Determine which port number or range of numbers the application uses (for arc that number is 55000)**
  2. Launch a web browser from a device that is connected to your router’s network.
  3. Enter A login window displays.
  4. Enter your user name and password. The user name is admin. The password is the one that you specified the first time that you logged in. The user name and password are case-sensitive. After logging in, The BASIC Home page or Dashboard displays.
  5. Select ADVANCED > Advanced Setup > Port Forwarding/Port Triggering.
  6. Ensure that the Port Forwarding radio button is selected as the service type.
  7. Click the Add Custom Service button.
  8. In the Service Name field, enter a descriptive name (Roon Arc.)
  9. In the Service Type field, select a protocol.
    If you are unsure, select TCP/UDP.
  10. In the External Starting Port field, enter the beginning port number(55000.)
    (If the application uses a single port, enter the same port number in the Ending Port field.
    If the application uses a range of ports, enter the ending port number of the range in the External Ending Port field.)
  11. Specify the internal ports by one of these methods:
  • Leave the Use the same port range for Internal port check box selected.
  • Type the port numbers in the Internal Starting Port and Internal Ending Port fields.
  1. Type the IP address in the Internal IP address field or select the radio button for an attached device listed in the table.
  2. Click the Apply button.
    The service is now in the list on the Port Forwarding/Port Triggering page.

An important thing to note - make sure the port number you enter in your router settings is the same number you see when you head into your Roon Settings>Roon Arc.

(**If you get an error saying the port is in use for 55000, that means that the current port is already being used by another program on the same computer as your Roon Core. You’ll need to enter another port in Roon, in the Roon ARC tab of Settings. You can enter any available port in the 10,000 to 65,000 range.)

Let me know if the above helps! :pray:

Thanks. I have done what you explain in your message. I continue to have the same issue.
In Roon Core under the tab Roon ARC it is said the Roon ARC is not ready. The diagnostic data is this one:
“connectivity”: {“status”:“NetworkError”,“status_code”:504,“error”:“error: Error: ETIMEDOUT, response code: undefined, body: undefined connected? undefined”},
“external_ip”: {“actual_external_ip”:“”,“router_external_ip”:“”},
“status”: “status”: MultipleNatFound
“natpmp_autoconfig”: {“status”:“NotFound”},
“upnp_autoconfig”: {“server_ip”:“”,“found_upnp”:true}

Thanks for your help.

Hey @Jean-Claude_Mounir,

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 there is a redundant layer of network address translation preventing port forwarding.

This can either be at the local-network level (commonly as a result of two routers), or at the level of your service provider (in the form of carrier-grade NAT).

You may need to reach out directly to your service provider to ask if they support port forwarding; this question will often enough to prompt them to explain whether or not the carrier-grade NAT they’ve implemented can function with ARC.

More specifically, you can pass along the following questions:

  • Have you implemented carrier-grade NAT for my account level?
  • Have you fully implemented IPv6, or do you have IPv4 addresses available?
  • Can I request a static IPv4 address to support port forwarding?
  • Are there any ports you have reserved at the ISP level I should be aware of?

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