· I use a single personal router not provided by my ISP
ARC Status
· ARC is *Ready*
Describe the issue
Using a Mac mini as server. Has been working for months; suddenly, it cannot find an open port; no matter what number port I use it says 'port in use.' ARC on phone cannot connect to server. I've reinstalled, restarted, deleted app and reinstalled, deleted Roon app from Mac mini, reinstalled; nothing works. I tried installing Tailscale as well--no help there either. There is no Roon chat support service, no phone support service, both of which are absurd; if this is not resolved ASAP, I will be cancelling.
Describe your network setup
Xfinity; router is Xfinity Gateway XB7. All connected using wifi. operating on Mac SONOMA 14.8.1
Your logs show what happened. From July 9 through August 13 your server was using port 55000 and ARC was working. On August 13 at 18:48 the port was changed, and the log shows it move to 57000, then back to 55000, then to 55002 within about twenty seconds. Your settings currently have a manual ARC port of 55003. ARC has not worked since that afternoon.
The port has to match in two places, and right now it does not. Changing it in Roon tells your server which port to listen on. It does not change the port forwarding rule in your router, which is still pointing at the port you were using before. So traffic from ARC arrives at your Xfinity Gateway, gets forwarded to the old port, and finds nothing listening there.
This is covered here, in the sections headed Port in use and Using a different port:
What we suggest, and it is quick.
Please pick one port and use the same number in both places:
In Roon, go to Settings, then Roon ARC, and note the port shown there.
In your Xfinity Gateway, edit the port forwarding rule so that both the internal and external port match that number, pointing at your Mac mini’s IP address.
Back in Roon, press the refresh arrow on the Roon ARC tab to retest.
If Roon tells you the port is in use, please choose a different number anywhere in the 10,000 to 65,000 range, then set that same number in the router. Any free port works, there is nothing special about 55000.
One thing worth checking while you are in the router: your Mac mini needs to keep the same IP address, otherwise the forwarding rule will point at the wrong machine after a reboot. A DHCP reservation for it in the Gateway is the simplest way.
If it still does not connect after that, please send us a screenshot of the Roon ARC, the router port forwarding settings page including the diagnostic text, and we will take it from there.
Thanks for the screenshots, they pointed us somewhere new.
It looks like you have a second Roon Server on your network. Your MacBook Air is running one alongside the Mac mini, and that’s almost certainly what’s behind this.
Two Roon Servers on the same network both try to claim a port mapping on your Xfinity gateway. Whichever one asks first gets it, and the other is told the port is taken, which is the message you’re seeing. It doesn’t matter which server you consider “the real one”; an inactive Roon Server still does this. That also explains why every port number you try comes back the same way. Your logs show the port jumping from 57000 to 55000 to 55002 in about twenty seconds, which is what it looks like when two servers keep re-claiming ports from each other.
The fix is to get down to one Roon Server:
On the MacBook Air, fully quit Roon Server. If you want to keep using the Air to browse and play music, install the regular Roon app instead, that’s a remote and won’t compete for ports.
Restart your Xfinity Gateway. This clears any stale port mappings the Air left behind.
Restart the Mac mini, then open Roon and check Settings > Roon ARC. The port should now hold.
Once it does, set your router’s forwarding rule to that same port number and add a DHCP reservation for the Mac mini so its address doesn’t change.
One note on the screenshot from your phone: the Apply button was greyed out, so we can’t tell whether that 15666 rule was ever actually saved. Worth confirming it’s in your active port forwards once you get to step 4.
Let us know how the Mac mini looks after the Air is out of the picture.
