ARC doesn't connect to core located on my QNAP NAS

Roon Core Machine

Core version 2.0 (build 1128) production located on my NAS : QNAP (QTS 473)
Control version 2.0 (build 1128) production located on my Imac OS Catalina 10.15.7

Networking Gear & Setup Details

NAS connected to Synology Router with ethernet wire
Imac connected to Synology Router with ethernet wire + wifi

Connected Audio Devices

Use a DAC

Number of Tracks in Library

125 000 tracks

Description of Issue

I am unable to get ARC to connect to my core which is on a QNAP NAS.

I tried with the Automatic Configuration → Unsuccessful

I followed all instructions of the ARC Port Forwarding troubleshooting FAQ

  1. I enabled UPnP on my QNAP NAS and on my Synology router. The mapping is OK

  2. I tried the Manual Port Forwarding with the static IP address of my Roon core located on my NAS
    I created a new port forwarding rule in your router that uses these 3 pieces of info
    IP address: The IP address of my roon core
    LAN/Private/Internal Port: Port 55000
    WAN/Public/External Port: Port 55000

I tried unsuccessfully several ports (35575 / 55002 / 55000 / 65000)

The error message is :

I also followed instruction in this thread

I reinstalled codecs of my QNAP System’s ffmpeg binary that had been stripped by the update.
At the beginnning, it was indicated “System default”

So I downloaded ffmpeg for amd64 architecture on johnvansickles website
ffmpeg-git-amd64-static.tar.xz - md5

I extract the ffmpeg file, copied it to my RoonOnNAS/bin folder (which was emptied) and restarted my Roon Server
Afterwards the QNAP message was different : User supplied version

To be exhaustive, I tried with / without activating

  • NAS antivirus
  • NordVPN on my iMac

I also tried from my Android phone (still unsuccessfully)

:sos:I don’t know what to do as I don’t have any technical skill / knowledge (port setting, protocol, etc.)
I’m all the more disapointed that I specially updated my roon versions + upgraded my iMac to benefit from ARC capabilities.

:pray:Thank you in advance for your precious help ! :crossed_fingers:

I have same issue although I can get ARC to work if I turn off Antivirus. Not a permanent solution as zi need antivirus turned on.

I also tried to open firewall port on Synology as well, as indicated on thread link below.
But still doesn’t work :smiling_face_with_tear:
(Even with anti virus + VPN turned off)