Unable to connect to ARC on cellular after reinstalling Roon and Tailscale (ref#YNB865)

[technotrout]

Network Setup

· I use a single personal router not provided by my ISP

ARC Status

· ARC is *Not Ready*

Roon Error Code

· The ARC settings page says "Not Ready," but I can still connect to ARC via cellular data. I'm having another problem.

Describe the issue

(note: I posted this last week and prematurely thought it was resolved. I still can't actually play anything or connect to ARC when on cellular.)

I've been successfully using ARC via Tailscale for months with no issues, until I recently re-installed Roon (due to the constant issue of Audio Sources disappearing). After re-installing, I was able to restore my Roon backup and can access it from mobile devices within network, but can no longer connect to ARC when outside of the network. I tried re-installing the Tailscale Docker (I'm using a UGREEN NAS as my Roon Server) and the connections all show connected/green, as well as re-installing ARC on mobile, toggling all connections on/off, restarting Roon Server, etc. Anything I'm missing?

I've also tried to go the static IP/port forwarding/UPnP route which has yet to work for me, with numerous errors.

{
"ipv4_connectivity": {"status":"NetworkError","status_code":502,"error":"error code: 502"},
"external_ip": {"actual_external_ip":"107.aaa.bbb.ccc","actual_external_ipv6":"null","router_external_ip":"null"},
"natpmp_autoconfig": {"status":"NotFound"},
"upnp_autoconfig": {"status":"NotFound"},
"multinat_autoconfig": {"status":"Failed","error":"Network Trace Failed"}
}

Describe your network setup

- UGREEN DXP2800
- linked via WiFi/Ethernet, ASUS RT-AX5400 router (no additional/ISP router)
- all devices connected successfully on Tailscale
- macOS Tahoe 26.5.1, iOS 26.5

[connor]

Hi @technotrout,

Thank you for your post.

The diagnostic snippet in Roon Settings → ARC won’t apply if you’ve installed Tailscale, since it only pings the server using the open port to test if port forwarding has been correctly configured.

What do you see currently in ARC? Usually, restoring a Backup will erase the association between ARC and your database, and you’ll need to reinstall ARC as well to re-sync. This is an unfortunate reality of the current implementation, but we’re working on a way to make ARC more resilient against database migrations.

Try reinstalling ARC itself on the phone. The existing Tailscale connection should work fine if you still have the app on your phone and computer.

We’ll watch for your reply. Thank you!

[technotrout]

Thanks, I hadn’t tried re-installing ARC on my phone, but after doing so it is still unable to connect with my Roon server on cellular. Though I now get a definitive “Port Forwarding Issue” error message in the ARC app, with green success dot for Cloud and red for Roon Server, whereas before they’d both just endlessly pinwheel on “Searching for your Roon Server.” But still unable to play any music.

And yes sorry, understood re: Tailscale vs Roon Settings. I meant I’d been re-attempting Port Forwarding with my router sans Tailscale, but could not find success there either.

Appreciate the help

[vadim]

Hello @technotrout,

Thank you for giving that reinstall a try and sharing the results! The change from an endless pinwheel to a definitive “Port Forwarding Issue” error is actually a helpful clue.

Because you are trying to use Tailscale, seeing a “Port Forwarding Issue” in the ARC app is expected, and you can safely ignore it.

To help us isolate exactly where the communication is breaking down, could you please confirm one detail: Are you able to successfully connect to ARC, sync your library, and play music when your phone is connected to your local home Wi-Fi?

If ARC works perfectly on your local Wi-Fi but fails on cellular with Tailscale active, it tells us that Roon and ARC are handshaking correctly, but the Tailscale Docker container on your UGREEN NAS might be missing the specific subnet routing or network flags (like the –tun flag) that were present before you reinstalled it.

Looking forward to your reply so we can get this sorted out!

[technotrout]

Edit: disregard and see my additional reply below for solution

Thanks for this! Definitely on the right track with the UGREEN/subnet callout.

@vadim

Are you able to successfully connect to ARC, sync your library, and play music when your phone is connected to your local home Wi-Fi?

yes!

@vadim

If ARC works perfectly on your local Wi-Fi but fails on cellular with Tailscale active, it tells us that Roon and ARC are handshaking correctly, but the Tailscale Docker container on your UGREEN NAS might be missing the specific subnet routing or network flags (like the –tun flag) that were present before you reinstalled it.

Just need some help here please, I’m now noticing Tailscale shows a “Subnets(!)” error message in the admin console: “This machine has unapproved routes. Review this from the ‘Edit route settings…’ option in the machine’s menu.”

Sorry but I’m unclear where a network flag like -tun would go?

Here’s my current docker compose configuration. I also tried pointing TS_ROUTES to the exact subnet address of the UGREEN, but that didn’t seem to work. Is the port correct? Networking is admittedly not my strong suit, I thought /24 was kind of the default control port?

services:
tailscale:
container_name: tailscale
image: tailscale/tailscale:latest
restart: always
volumes:
- ./tun:/dev/net/tun
- ./lib:/var/lib
environment:
- TS_AUTH_KEY=tskey-auth-xxxxxxxxxx
- TS_STATE_DIR=/var/lib/tailscale
- TS_ROUTES=192.168.50.0/24
network_mode: host
privileged: true

[technotrout]

@vadim actually, disregard the last reply, aside from the Tailscale “Subnets!” error message part. I didn’t realize the setting was right there in the Tailscale admin console. Just needed to check the box and save

Confirmed ARC now plays via cellular. Appreciate the help all!