Roon ARC: One Device Works, Two Don't, Same Core


Ubuntu 20.04 LTS, dual Ethernet, 24 GB RAM, 512 GB SSD boot, 20 TB SATA local storage
Roon v.2.0 (build 1133)


iPhone 8 iOS 15.7 64GB (38GB available)
iPad Air 2 iOS 15.6.1 16GB (4GB available)
iPad Pro (12.9") iOS 15.6.1 128GB (99 GB available)


Dual gigabit Ethernet on Core
Two Ubiquiti Edgerouter X routers, firmware v.2, in parallel to Internet
WAN ports have static routable IPs
Core has access to two LANs; Roon Remotes confined to single LAN
Identical setup on each router except for WAN and LAN addresses
Each router has port forwarding applied to respective server IP




1.06 million, mostly FLAC
TIDAL and Qobuz services enabled


Out of three devices tested Roon ARC only works (connects/syncs) with the iPad Pro above. Since the ARC debut neither the iPhone nor the iPad Air has successfully completed its first sync. All devices register successfully.

The server has undergone several restarts. The mobile devices have had the ARC application deleted and reinstalled many times.

At login, Roon ARC server is located quickly.

Upon initial connect, Syncing with Roon Core for first time: “There was a problem syncing to your phone.”

Subsequent attempts to sync: “Searching for Roon Core… This is taking longer than normal.”

It should be noted that there is no WiFi in the ‘Home’ location. It is an institutional network that offers only wired Ethernet. The iPhone and iPad Pro were tested locally using a Lightning-Ethernet adapter. When ‘Away’ the same WiFi network was used by all devices.

Cellular data (iPhone only) was also tried without success. Same results as above.

Can anyone offer any suggestions on how we might get the iPhone and iPad Air to successfully connect to ARC?

-Thank you


Server Side

  • Update the Roon Server to current (latest) release.

  • Stop the Roon server.

  • Rename the Server Database folder (/var/roon/RoonServer/Database) as backup.

  • Restart the Server. Verify that a new Database folder and contents were created.

Client Side

  • Each mobile client was handled differently.

  • iPhone: Delete the iOS app from the device. Download fresh copy of iOS ARC app.
    Attach iPhone to Home network (LAN) using Lightning Ethernet adapter. Verify network connection and IP address.

    Launch ARC app, sign-in and initialize program. Synchronize collection and verify operation.

  • iPad Air: Reset iPad to Factory load. (This was done to create as much free space as possible.) Download iOS ARC app. Attach iPad to Away network using WiFi.

    Launch ARC app, sign-in, connect, and initialize. Synchronize collection and verify operation.

  • iPad Pro: No changes to the device, app (the app had been updated already), or its installation. Launch app. Synchronize collection and verify operation.

All three devices now connect to the server via ARC as expected. Of the three the iPhone 8 was the hardest to get working and required several attempts (maybe 8) to connect and synchronize the collection.

Both iPads connected right away and without event.

A full workout of search, download and playback is still forthcoming.

1 Like

Hi @KGLT_Radio,

It sounds like you were able to get things working before we were able to view your case. Can you confirm that things are still running as expected?


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