Hi, I don’t find why it doesn’t work. Thank you for your help.
{
“ipv4_connectivity”: {“status”:“NetworkError”,“status_code”:504,“error”:“error: Error: ETIMEDOUT, response code: undefined, body: undefined connected? undefined”},
“external_ip”: {“actual_external_ip”:“82.aaa.bbb.ccc”,“actual_external_ipv6”:“null”,“router_external_ip”:“null”},
“natpmp_autoconfig”: {“status”:“NotFound”},
“upnp_autoconfig”: {“status”:“NotFound”}
}
Have you set a port forwarding rule or enabled UPnP in your routers settings?
What ISP do you use? Do they use CG-NAT? CG-NAT prevents port forwarding from working.
Usually, in the presence of a CG-NAT connection, Roon gives a ‘MultipleNatFound’ error in the diagnostic text but there have been cases when that was not the case.
If you look a the Web UI of your router (that your Roon server is connected to), does the WAN IP address start with 82. (ie does the obfuscated 82.aaa.bbb.ccc actuall_external_ip address in the diagnostic text match the ip address of your router (Do not post this ip address on this forum).
For a more exact comparison you can visit a site like whatismyipaddress.com and compare the IPv4 address that you get with the WAN side IP address of your router.
You can tell us whether or not a match is found - but do not post images or text that includes the WAN side ip address of your router or what is seen on whatsmyipaddress.com.
If the ip addresses do not match, then either you have a second router between the Roon Server and the ISP connection or the ISP is using CG-NAT.
If the ip addresses do match, then it must be something else. In that case, I would start by looking a any firewall on your Roon Server machine (you do not say what kind of Roon Server you have (ROCK/Nucleus, PC [Windows or Linux], or Apple Mac). See:
And port 55000 is what’s shown in the ARC settings on your core? I ask because it can move.
192.168.1.254 is the IP address of your core, or gateway? Your need to port forward to/from your Roon core address.
There’s something I do is wrong but I don’t find what it is. 
The IP address is not the address of my core.
Then it’s not a surprise that it doesn’t work. The ARC traffic has to be forwarded to the machine where RoonServer is running (your core), of course.
Find out the IP address of this machine and use it in the port forwarding rule as the „Destination“ address.
OK but I don’t find IP adress of my Nucleus. :sob
Sorry !!!
Can you open the web admin interface of the Nucleus in a web browser by going to http://nucleus or http://nucleus.local ? (Assuming that it’s a Nucleus. Otherwise replace nucleus in the http address with nucleusplus, nucleusone, or nucleustitan)
The IP address you should be using is right next to the ARC port number in the Room app ARC settings screen, for example:
If its not there, click Show Advanced, and copy the „local network address“.
Then you have another router in the path which also needs the port forwarding rule in it - unless you can move your Roon core to the primary (ingress/ISP) router.
—> ISP router ------> intermediate router -------> Roon Core
192.168.1.X 10.0.0.X 10.0.0.3
← 55000 ← 55000
Ok thank you, i will see tomorrow. Maybe i will try an other connection.
Note: In the little diagram that @mikeb posted above, the intermediate router will have two ip addresses (a WAN side ip address which should start with 192.168.1 and a LAN side ip address (starting with 10.0.0.).
On the ‘ISP router’, you want to create a port forwarding rule to forward TCP connections on the ARC port to the WAN ip address of the intermediate router (192.168.1.x).
Nucleus was connected to my Netgear Orbi. I connected it directly to my internet box and ARC immediately connected with an IP address 192. XXX.X.XXX
Now Roon can no longer find my KEF LS50 Wireless II speakers
who are Roon Ready. 
That’s because they’re probably also on the Netgear Orbi network…. Either move them to the „internet box“ router, or move your Roon core back, and put a port forward rule on the Orbi.
I did a complete reset of the Kef speakers, connected to the internet box (like Nucleus) and everything works perfectly.
Thank you all for your advice, you are great guys.
Long live to rock’n Roll.
Thank you again. 
