Is it a dumb switch or does it have a web interface? If it doesn’t, invest in a ‘managed switch’ so you can access the info inside. They start at £20.
I’d not do port forwarding unless you know exactly what you are doing. I cannot believe it is necessary.
If you have identified the IP Address, what happens when you try that in a web browser?
Is the ethernet cable connected to the BMS port or the dongle port?
I doubt it. Hopefully you have not opened your entire network to port 22!
I agree, not sure why you would need port forwarding on. If you type the allocated IP address into your browser what do you get? Opening internal devices via port forwarding can leave your network vulnerable 
John
If it isn’t port 22, what should it be?
I have set up port forwarding (or tried to) for just the one device.
My advice is to step back and be sure about what you are doing and not do random things. Opening ports safely is extremely tricky.
??
From what I can see (and I do not have one and have not found any great info), the BMS (Building Management System) port is different to the Wi-Fi ‘dongle’. The Wi-Fi dongle should, as the name suggests, connect by Wi-Fi not be a cabled connection.
Hi,
looking at the manual for the inverter you say you have it says
Note！
485 commuication and LAN commuication have respective RJ45 port
interface inside of the inverter. But them share the same connection port
(COM port) on the bottom of the inverter. 485 communication is default,
if user wants to use LAN function, it needs to open the lid cover to operate.
Have you done this?
The picture you posted does not look the same as the manual picture
This is a link to the manual
John
However if you are using their “pocket LAN” this should help you
SolaX Pocket LAN Set-Up - SolaX Power
This seems to indicate that once connected up you need to go to their website to register, did you do this?
John
It looks like you might be onto something.
What is the “lid cover”?
This is the manual.
It’s x1-fit-5.0-w
I’m not sure you have what you think you have.
Do you have a Wi-Fi module.
It says LAN is between router and inverter not the internet. It mentions RS485 previously.
It appears you need the Wi-Fi module to communicate with a monitoring-website.
What does the installer say?
[edit]
It seems you need the Wi-Fi module even if connected via the LAN.
How confusing!
The inverter is connected to the router via the ethernet socket. That socket has a cable that goes to a switch and from the switch to the router. We thought this would be better than wifi because the wifi is patchy in the house.
It seems odd that we would need both a LAN dongle and a wifi dongle. That can’t be right? Whether we have LAN or wifi dongle, both would connect to the router before going to the internet.
Quite possible. The Wi-Fi dongle might manage the authentication to the web based system.
In my quite extensive experience with solax I’ve never had to open ports. Some solax have an internal network rj45. Some use an external dongle, these are available in lan and wifi. solax have had a lot of issues with dongle/inverter intercompatibility previously though i can’t find the reference document at the moment.
My gut tells me there’s a problem with your switch/local network configuration.
Things I’ve done in the past to prove issues lie within a customers home network include:
Directly connecting to the hub with a long data cable.
Plugging a wifi booster in access point mode or a laptop into the data cable that’s the inverter is using.
On occasion I’ve totally circumvented the home network by creating a wifi hotspot on my phone using mobile data. In your case using a usb c to ethernet adapter might be possible. Also using a WiFi booster connected to your phones wifi and the inverter plugged into that with the data cable would do the job.
Finding simple ways to prove your network cable is where I’d start. Then rule out the switch. If you can’t see the MAC on your router table then something is going wrong. Once you’re certain that it should be working, note that these dongles have been known to fail on firmware update and also on occasion with no discerning cause… Prove that it should work, and then get in touch with solax with your method and conclusions.
New here, saw this Solax thread. I tried for days to connect to my dongle. The servie people at Solex were really helpful but I decided the dongle was too far (or too many obstacles) from the router - added a WiFi booster and worked straight away. The strange thing is the dongle seems to put out more signal than the router does.