Hi Sam,
I’m sorry to hear you’ve hit up against some difficulties.
In the first instance I’d love to double check the exact sequence of events you are following. I’m assuming you’ve followed steps 1-9 as described here and are receiving the error you quoted after pressing the Get Authorization button. Is that correct, or are you seeing this at some other point?
Secondly, would it be possible to see your system information, which you can share via a private reply?
Thanks!