Connection Issues with WHx Gen3

In brief:-
I cannot get the inverter to connect to the router (it did do, up until about 10 days ago).
I cannot connect to the inverter web interface reliable - it's very unstable and disconnects after a few seconds.
This is my parents' system. I have Gen2 system with a dongle at my home, and have no issues like this.

Inverter to Router
We have an EE 4G router that supports 2.5/5/6ghz wifi. The inverter has been connected to it for several months, but after the router was rebooted 10 days ago, it is no longer connecting. I've tried everything I can think of: disabling 5 & 6 ghz and changing default channels. There's nothing I can see that is blocking it. Lots of other devices are connected to it with no issue.

Connecting to Inverter Web Interface
When I go into the computer WiFi, I connect to the WHx network and it seems to connect OK. I get a 10.10.100.x address and the default gateway gets set to 10.10.100.254. I then attempt to connect to 10.10.100.254 and usually by the time I've got that far the network has disconnected. Sometimes if I'm quick I can get logged in, but by the time I get anywhere it's disconnected. If I'm really lucky I can get into a screen, change something and reboot it before it disconnects. Usually that involves a lot of reconnecting to the WiFi and refreshing in the browser. With a great deal of persistence and much swearing I have managed to re-select the network and enter the password. I've also managed to change the channel in the AP setting screen to try and get a more reliable connection, all to no avail. The connection to the inverter is still very erratic, even when I'm right next to it. The signal indicator says it's good (3/4 bars).

I've compared the experience to what I have at my home. With mine, I can connect to the dongle WiFi easily, the connection is stable, and I can get into the web interface with no issues at all. This leads me to think that a) there is some significant interference that's affecting the inverter's WiFi (although I've tried channels 1,6,11 & auto), or b) it's faulty.

Has anyone got any further suggestions on what to try? I'd contact the installer, but they did a bunk shortly after installing.

Strange, it could be a faulty dongle but seems unlikely if its worked fine for such a while.

On the EE router disabling 5 and 6GHz is definitely needed, the inverter only connects on 2.4 and if 5 is turned on then often this will stop it connecting. Have a look on the router and see if there are things like ‘fast roaming’ set, also turn these off.

BUt this doesn’t explain why you can’t connect reliably to the inverter web interface, that should be fine regardless of the inverter connecting to your wifi

MrTim Why did the EE router reboot? If it was a f/w update then check what the security settings are on the wireless section of the router. If it mentions WPA3 then the dongle might not connect, you'll have to select WPA2.

geoffreycoan actually, even when I did get it to connect the the EE router many months ago the connection to the inverter was very unstable. It was only by sheer persistence for many hours that I was able to get as far as reselecting the new network and entering the password. So that part has always been bad, but I didn't think I'd need to ever go into it again.

Vestas it was rebooted because my nephew went in there to look at the NAT settings to try to sort out his Xbox issues. I think he turned on uPnP, which I have since turned off.

I believe it's set to a mixed WPA2/WPA3. Not entirely sure as I'm not there now and I can't remember exactly what it's called. I don't think that was changes though but I will change it to WPA2 and try it.

If you don't want to lose any more time, and are not at that location very often, consider buying another device, just to create a new separate network for GivEnergy equipment.
It can be single access point or router from eBay, or more expensive powerline adapter with WiFi function. eBay option will cost you £5 or £10.

Thanks all. I've got the inverter connecting now. It was set to WPA2/WPA3 and also had 5ghz enabled. As far as I'm aware neither of those had been changed. On my own gen2 system I have 5ghz enabled and it's quite happy. Anyway, after disabling it and switching to WPA2 it connected. Not sure which one was the issue.

The unstable connection to the inverter web interface is still an issue though. I don't know what the problem is with it, but I suspect it's faulty. Is there a way to connect directly using a cable on a gen3?

MrTim could it be the device you was using to connect to the inverter?

Modern phones, tablets, and even newer versions of Windows like to switch WiFi to find one with am Internet connection.

I found that configuring my inverter dongle via a laptop was so much easier than via a mobile phone, it kept jumping off the inverter dongle WiFi.

Might even have to turn off auto connect on other WiFi networks on the laptop temporarily to force it to stay on the WiFi you choose.

But anyway, once it's all configured, there should be no need to join that WiFi again, so you can forget it on your devices (oh and make sure the WiFi access point is secure as per the guide on the KB site!).

It's not. Have tried a couple of laptops and tablets, phones. Have set them to automatically connect and set their normal networks to not automatically connect. I look after 2 systems. My own personal system is fine and the connection is very stable, but this one is terrible. It's pretty much unusable, even when you're right next to the inverter. To get logged in and change just one setting could take an hour of attempts and reconnections. If you ping the inverter, it goes from 1ms response to time outs.

I can only think it's some kind of interference, or it's faulty.