I recently bought a Mitsubishi ASX PHEV (2024) that has Android Auto. Roon Arc worked just fine. I could access Qobuz and my own library while on the road. However, since a few weeks, ARC can no longer find or connect to my Nucleus, even when I’m parked right next to the house at 10 metres from the Nucleus. (I did have to take the car to the dealer recently because all audio had stopped working and they reset the car’s computer. Maybe that messed up something)… My phone is a Samsung Galaxy A53 5G. Inside the house, the Samsung connects via RoonARC without any problem while on the Wifi in the house. In the car, it switches to an intenal wifi created by the car and ARC can’t find the Nucleus. Mobile data is enabled. Am I overlooking something? Is there anything I can try? I guess I can bypass the issue by connecting my phone over bluetooth to the AUX input of the car’s media system, but I would prefer to have ARC function c=via Android Auto. Hmm… I forgot to mention that I moved to another house ( ). As there was already an identical router there, I forgot to configure ARC settings there. So I dutifully enabled the UpnP thing. No success. I then manually portforwarded ARC to port 55000. I get the following error:
Thank you for the detailed information! Based on what you’ve shared, the issue isn’t with Android Auto itself — ARC isn’t able to reach your Nucleus from outside your home network.
Since you’ve recently moved and changed routers, it’s likely that the current router setup (or mesh system) is blocking the port forwarding. Please check the following:
Confirm that the Nucleus has a static IP (192.168.1.190) so the forwarding rule always points to the right device.
Disable UPnP on the router and keep the manual port forwarding you set up for port 55000 TCP.
Make sure your TP-Link Deco units are in Access Point (AP) mode, not Router mode, to avoid double NAT.
After saving, reboot both the router and Nucleus, then test the ARC connection again.
If you’re still seeing the timeout error afterward, please share a fresh screenshot of your ARC connection status from Roon → Settings → Roon ARC and we’ll review the details.
Unfortunately, none of your suggestions had any effect.
I think the Deco is only an access point. The deco app doesn’t have any settings for router/access point.
I am getting confused: when in my car, I have bluetooth on plus mobile 4G access. The phone says that I am connected via Bluetooth for calls, not for sound, and the wifi says it’s using a special car WiFi.
Amyway, I thought that ARC communicated with the Nucleus over 4G. My Nucleus is connected to the router via ethernet.
The only detail that may be relevant is that the Deco mesh points use their own IP range (192.168.68.×). My network uses 192.186.1.x Only the “head” mesh point is in the network range, but wifi access is fine.
I have made the screenshot you asked for, but I can’t figure out how to paste it here.
The “add images” button doesn’t help…
Please advise me on this.
Frustratingly, I have to type all this on my phone as I always get the login error of failed recaptcha when trying to use my windows pc to respond to the topic.
Thank you for the update, and for sharing those details — they help a lot.
Let’s address both parts of what you’ve described: the ARC connection and the login issue on your Windows PC.
ARC Connectivity
From your description, it sounds like your network currently has two IP subnets:
The main router uses 192.168.1.x
The TP-Link Deco mesh creates a second range 192.168.68.x
If your Nucleus is connected to one of the Deco mesh units rather than directly to the main router, the port forwarding on the main router will not reach it — Deco is performing NAT on its own subnet (192.168.68.x). In that case, your router’s rule for port 55000 forwards to the Deco, not to the Nucleus behind it.
There are two possible ways to fix this:
Double port forwarding:
Forward port 55000 TCP on the main router to the Deco’s IP, and then on the Deco forward the same port to your Nucleus (192.168.68.x).
This ensures the incoming ARC connection passes through both layers of NAT.
Disable DHCP and routing on the Deco (Bridge or Access Point mode):
This merges both networks (192.168.1.x and 192.168.68.x) into one and eliminates double NAT entirely. After doing so, your existing port forwarding rule on the main router should work immediately.
Without one of these changes, ARC will not be able to reach your Nucleus, since the Deco will block unsolicited inbound connections from the internet.
Here’s what we suggest:
Confirm where the Nucleus is connected — ideally it should be wired directly to the main router, not behind the Deco mesh.
Make sure the Deco system is in Access Point (AP) mode, not Router mode. This will merge both subnets into one (192.168.1.x).
Once both the Nucleus and your phone are on the same network range, please re-check your port forwarding rule for port 55000/TCP.
Confirm that the rule points to the static IP of your Nucleus (192.168.1.190).
Disable UPnP and rely on the manual forwarding only.
Reboot the router and the Nucleus, then try the ARC connection test again.
If you’re still getting a timeout afterward, please attach a fresh screenshot of Settings → Roon ARC showing the full diagnostic text (you can drag and drop it into the reply box on the forum).
Login Error on Windows (“Recaptcha Failed”)
This behavior is typically caused by cached browser data or privacy settings that interfere with the login process. Please follow the steps below on your Windows PC:
Clear Browser Cache and Cookies
In Chrome:
Open Settings → Privacy and security → Clear browsing data → select Cookies and site data + Cached images and files, then click Clear data.
Check Site Permissions
In Chrome, go to Settings → Site Settings.
Ensure that Cookies and JavaScript are allowed, and Pop-ups and redirects are temporarily enabled.
Try an Alternate Network
Switch between Wi-Fi and mobile tethering, or vice versa. This resets the DNS path and can resolve the Recaptcha error.
Verify System Time
Ensure your PC’s system clock and timezone are set correctly and synchronized automatically.
Could you please confirm:
Is your Nucleus connected directly to the main router, or to one of the Deco units?
Did you configure any port forwarding on the Deco itself, or only on the main router?
Thanks for your detailed response. I installed Chrome (I normally use Firefox) and was able to log in here now (such a relief to be able to use a regular keyboard!)
First of all, my Nucleus is ‘hard-wired’ via ethernet to the router via a switch, so there’s no wifi involved there. I only use the deco mesh wifi to access Roon on my phone or tablet and that works just fine. So, no conflicts there. (I can also use the WiFi network from the Nokia router itself, but that doesn’t quite reach the living room, hence the deco mesh points.)
By the way: I was wrong about the deco: It was indeed in Router mode, but I found the setting and now all the mesh points are in the same 192.168.1.xxx range.
I have already disabled UpnP, made the IP-address for the Nucleus static and checked the port forwarding to 55000/tcp. However, the router now says: “The Input Internal Client IP is not in subnet of host address!”
The forwarding rule is:
Okay, still no connection to the Roon server from my car. Roon Arc settings there reports “port forwarding issue” so there is still something amiss there. As soon as I move away from the car and are on my own wifi network, ARC works fine (which makes sense).
Is the message “The Input Internal Client IP is not in subnet of host address!” relevant and what can I do to remedy that?
Thanks for bearing with me!
Update: I have now established that I can only connect to my Roon Server when I am om my own wifi network. From my neighbour’s wifi it doesn’t work either. So it’s definitely not android auto causing this.
Update: When I look at the ARC settings in Roon, under Advanced I see the Nucleus info and there it says the IP4 adress is 62.45.66.83. Is that weird or okay? I thought the nucleus’ static IP address was 192.168.1.190 (like it says higher up on this screen).
I have no idea if this means anything but I thought I’d mention it.
I’ve set the port forwarding rule to 55000 in both wan and lan fields and don’t get error messages when saving this. Curiously, when I choose “Nucleus” as internal client this changes to “custom setting” when saving. I’m just saying…
Most major internet service providers in your geographic region have implemented carrier-grade network address translation (CG-NAT) that blocks port forwarding. Neither auto-configuration nor manual rules will traverse this layer of CG-NAT.
I recommend reaching out to your service provider directly to inquire if they are using CG-NAT and if they have any external IPv4 addresses available for your account. Some providers offer this feature for free or for a small fee.
CG-NAT is unfortunately outside of Roon’s ability to control. If your provider can’t offer an external IPv4 address, let us know, and we can talk through some workarounds.
Hi Connor,
I think you nailed it. My ISP is Delta in the Netherlands. I have contacted them and they will turn of CG-NAT in my router, which will have a new IP address and then I will be able to implement port forwarding.
This will take a few hours.
Should I then first try the UPnP method or just stick with the manual figuration?
Anyway, let’s hope this works. I’m not holding my breath, but am hopeful.
Thanks for all the support. Will post the outcome here.
Thanks for the update! Testing out NPnP first is definitely something you can try - and if it’s giving you issues, you can disable it and revert to your manual port forwarding rule.
Unfortunately, it looks like my ISP has not yet succeeded in turning off CG-NAT in my routermodem, as I don’t see any changes in ARC’s behavior. They said I would get a new IP address, but I’m not sure where to check for that. Is it the address listed under advanced on the RoonARC settings page that I mentioned earlier?
I must say this ISP doesn’t let the Nokia router reveal much (not even what Internet speed I have!)
Will try to contact them again and check on their progress…
Based on the diagnostic data, your connection is still showing the IP address 62.45.66.83, which indicates that your ISP has not yet removed the CG-NAT configuration. Once they switch your line to a public IP, Roon ARC should be able to establish the connection properly.
Please keep us posted on the ISP’s progress — we’ll be ready to re-check as soon as the change is confirmed.
Well, Hallelujah! My ISP finally succeeded in changing my IP address and removing CGNAT.
All is working as it should now. I can use RoonARC from the car, which is great for my upcoming road trip.
Thanks again for helping me out and pointing me in the right direction, Vadim, Connor and Benjamin!