Unable to Connect to Nucleus TITAN via ARC (ref#9J5ECN)

Support
1

Network Setup

· I use my ISP's router alongside a personal router.

ARC Status

· ARC is *Ready*

Describe the issue

I go into ARC press "connect" to my titan and a circle spins then stops and does that over and over until it says can't connect in pink at the bottom of my phone

Describe your network setup

ISP is AT&T, i have the BGW 320 moden and a Nighthawk RS700 router. Roon is running on Titan

2

Helo @Maxwell_Gosling

To identify the cause of the ARC connection failure on your Nucleus Titan, we need to clarify how your equipment is connected. Because you have two network devices (the AT&T box and the Nighthawk), they may be creating a routing conflict.

Please provide the following details:

  1. Physical Connection: Which specific box is your Nucleus Titan plugged into with the Ethernet network cable: the AT&T modem or the Nighthawk router?
  2. Router Settings: Do you know if your AT&T box was set to "IP Passthrough" or "Bridge" mode? (This setting forces the AT&T box to just pass the internet to your Nighthawk, preventing the two boxes from fighting over the network).
  3. Phone Connection: When the connection fails, is your phone using your cellular data (5G/LTE) away from home, or are you connected to your home Wi-Fi?
  4. Phone Type: Are you using an iPhone or an Android device?
  5. Security Apps: Does your phone have any active VPN apps, ad-blockers, or (if using an iPhone) iCloud Private Relay turned on?
Provide this information to proceed.
3

hey there -

  1. the titan is hardwired into the nighthawk router.
  2. AT&T moden confirmed in IP Passthru - i was initially having issues with double nat making roon arc not available within roon. it now says its ready to use in roon.
  3. on my phone i turned off wifi and toggled airplane mode on and then off to get a clean 5G connection to test
  4. iphone
  5. No VPN, etc. on the phone

Thanks

4

Hey @Maxwell_Gosling,

Thanks for the update! From a fresh Arc diagnostic report, we can see the core issue is a repeated authentication failure.

The app successfully discovers your Nucleus Titan and transitions through the connection states correctly, but then hits a wall trying to authenticate with Roon’s cloud servers.

Every connection attempt fails with auth invalid; reason: expired, and the POST requests to https://auth.roonlabs.net/1/auth/arcv2 are all returning errors. This is why you see the spinner loop, it keeps retrying and failing.

Importantly, ARC showing “Ready” in Roon just means your network port forwarding is configured correctly. It does not mean authentication tokens are valid.

Steps to try, in order:

  1. Sign out and back in to the Roon app on your phone. This is the most likely fix. The logs literally show the app transitioning to LoginState due to "reset app: logged out," suggesting the auth token is stale or corrupted. A fresh login should force new tokens to be issued.
  2. Also sign out and back in on the Nucleus itself (via the Roon app on your local network). Sometimes the server-side auth needs to be refreshed from the core end too.
  3. Check your Roon account subscription status at http://account.roon.com — an expired or lapsed subscription will cause exactly this auth expired failure.
  4. If the above don't work, try fully force-quitting the Roon ARC app on your iPhone, then reopening it on cellular (not Wi-Fi) and attempting to connect fresh.
Thank you! 🙏
5

Thanks for the this - the problem has resolved - seems like we are good to go - thank you

6

Hello @Maxwell_Gosling

We are happy to hear that the issue is solved. Enjoy your music