@xouross You need to setup port forwarding, I found this YouTube video on a similar but not identical Huawei router to yours, can you see if you have similar configuration screens? Port forwarding.
You also have multiplenat, do you have more than one router in your network?
The latest diagnostics you’ve provided suggest that your Core is having difficulty reaching Roon’s servers. There are several independent factors that can cause this error, and having two routers is the likely cause.
The ISP modem/router should forward port 55000 (or whatever is shown) to the mesh router. In turn, this should forward the same port to your core.
All devices should be on the same subnet, i.e., connect everything to the mesh router.
You will need to contact your ISP and ask if CG-NAT is being used. If so, then see if your ISP can provide a static public IP address for your connection. If this is possible, some ISPs charge for the static address, others may not.
One alternative is to use a VPN such as Tailscale. Some Roon users have had success in getting ARC to work over Tailscale, and example is here:
My ISP uses CG-NAT from what I have gathered the information and it’s not possible for them to remove CG-NAT, asking me to pay more for a static IP.
I have read the workaround using Tailscale, is there any documentation on how to do on a PC? I read the linked article and still confused. Thanks. I use this link in particular and get confused along the way.
You might try posting your tailscale questions in the tinkering section to see if someone can help you there. VPNs are considered “tinkering” to Roon support.
If you go the route of having your ISP give you a static IP, Roon support can certainly help. If you go this route and you call to have it done, let them know what you’re trying to do and they can help there too! Just explain that you’re doing port forwarding on 55002 and want it to go to your Roon core.