I’m reporting an issue with Roon ARC not working anymore on my Asustor AS5402T NAS, even though it was working perfectly when first set up.
Context
- I installed Roon Server on my AS5402T several months ago.
- Roon ARC was working fine initially, including remote access via port forwarding.
- At some point — possibly after a firmware update or other system-level change on the NAS — ARC stopped working.
Troubleshooting steps
ARC now reports:
“The selected port is already in use by another application.”
But all tests indicate the issue is not network-related:
- The selected port (e.g. 55111) is not in use (
netstatshows nothing bound) - I tested with
busybox nc -l -p 55111and confirmed that:- The port is reachable from the outside
- The port shows as “open” in tools like yougetsignal.com
- I tried several different ports — same result
- Even with Tailscale VPN, ARC still can’t connect to the Core
Final confirmation
I installed Roon Server on a Windows laptop (MSI) on the same network.
Result:
- ARC worked instantly
- Port binding succeeded
- Remote access is functional via both port forwarding and Tailscale
Likely root cause
It appears that recent system or container changes on the AS5402T prevent Roon Server from binding to external ports:
- Possibly due to restricted permissions
- Or increased sandboxing of services after a NAS update
This didn’t happen when I first installed Roon Server — it’s a recent regression.
Recommendation for affected users
Move the Roon Core to:
- A PC/Mac (even temporarily)
- Or a low-power always-on mini PC (NUC, etc.)
Use the NAS as a music library via SMB or NFS — that part works flawlessly.
Hope this helps others facing the same issue after updates on Asustor devices.
Best,
Olivier