Having problems connecting on certain mobile data networks

Hi guys.
I’m a Nabu Casa subscriber and recently I’ve had some issues connecting to HA using the Nabu Casa URL and the mobile app, it’s only when on mobile data away from home.
It will give me the error
failed to perform SSL handshake
So I emailed support to ask and he confirms my URL is working fine and possibly my internet on the phone.
So I have a dual SIM phone for work and when I was having issues I swapped over to data on the other SIM card which uses Vodafone (UK) and it connects straight away but whenever I go back to my normal O2 network I get that error and after about 5 attempts of pressing retry it will load but there will be a notification saying log in attempt failed.
Login attempt or request with invalid authentication from localhost ( See the log for details.
Has anyone had to this before as it’s happening on my wife’s O2 phone as well.

Probably some CGNat with a MITM service for proxying.

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I’m not exactly sure what that means ha ha.
Is that something I can fix or do I need to contact the service provider O2 ?

CGNat is is a NAT function, like the one you know from your own router.
That means one IP address on the side towards the internet and a lot more on the other side and to get things through you need to set up a portforward. Well, in the case with a CGNat your provider have the administration access to that router, so they need to set it up, but it is unlikely they want to on a cellular network.

They are then typically running a few proxies for HTTP/HTTPS traffic and routing the packets to these proxies, but routing of HTTPS only works if you can read what is inside the encrypted packets of HTTPS, so you need to set up a Man-In-The-Middle kind of attack to get that access, which can cause problems because some of the better services have a good secure setup and detect this setup as the “attack” it actually is.

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Hey @Steveuk did you ever sort this issue out?
I am on o2 uk network and since Tuesday i cannot access HA using duckdns domain on my phone.

No sorry I don’t know what caused it,
It just started working again one day and no trouble since last year.

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Bachoo, can you jump intot he thread here and compare your setup.
Same ISP? same Mobile ISP? same phone brand? Same setup, like DNS.over-http maybe?

I seem to have fallen into the same trap - on O2 and my remote access using the mobile network just stopped some months ago.
Did anyone find a solution at all?

I had to set up a private domain and it works fine now. Duckdns is not working for me on o2.

Hello, this started happening to me a while ago as well, O2 network AND Virgin Media.
To my knowledge, they have merged which is why I have no luck on my iPhone, iPad or Windows 10 PC. Someone mentioned it working on their Vodafone Sim card and others have said it works on the laptop, but mine does not.

I’m using Nabu Cloud, not Duck DNS, I assume these two are interchangeable because I’ve been using Home Assistant successfully for around a year to automate and control many things and I have not set up Duck DNS.

When you say you set up a private domain, do you mean e.g. mydomainname.com

No,t hey are not the same.
DuckDns requires an incoming connection directly to your router from your remote device, which might not be possible if the ISP is using CGNAT or block does in other ways.

NabuCloud is a server on the internet and works as a sort of relay.
You HA connection makes an outgoing connection to the NabuCloud server, which most ISPs allow.
The NabuCloud server then accepts the incoming connection from your remote device and then relays the data over the already established connection to your HA installation.

Seen from the remote device the connection technically works the same, but some ISPs block DuckDNS domains, where as NabuCloud’s domain should not be blocked.

Thank you for your response WallyR, you certainly seem very knowledgeable.

So I’m not sure what’s going on then, must be a O2/Virgin Media change or something. I have ordered a microHDMI to HDMI cable so will plug my TV straight into my Raspberry Pi 4, when it arrives, and hope something becomes apparent!

Due to my disability I was using HA with BroadLink for a lot of TV automations/scripts so it’s slow going in the meantime :frowning:

So I bought a new microSD, loaded raspberry Pi with home assistant, restored my backup and was happily going along all of Saturday afternoon and evening.
By the morning I couldn’t connect again.

I can only assume Virgin Media noticed the traffic again and blocked it.

I did buy a micro HDMI cable, and can see the console on my TV, but none of the functionality I had set up is continuing to work.