How to use Amber API?

Hi, I’m in Australia and trying to connect HA with the builtin Amber API/integration. This is the doco. I think I have the right API - it looks like this:
b5c7954f02dbde6eadfa6e9342ad2299 (modified from reality). When I try to use it in the integration I simply get “Invalid API key”. I can’t tell whether the request is even hitting the server and the server is responding with an error code or something else is the cause. I have seen something that says the Amber API is expecting your device to run on port 443 - is this right? Mine is running on 8123 and I haven’t got SSL working on it yet.

A little about my set up. I have a Synology NAS running “Container”. HA is loaded into this. HA was only installed a couple of days ago so it is the latest install: Home Assistant 2023.10.1 Frontend 20231005.0 - latest . I have HA talking to Fronius Invertor and smart meter

I may have posted this in the wrong place, my apologies please guide me to the best place to put it as I haven’t used this forum before