I discovered the issue (i think)... i have 1 x-aviation account per PC (prod, test 1, test 2) - each of the x-aviation accounts only work with the specific PC, i belive this is by design.
I made a mistake when i ordered the G500 - i used the incorrect account (test 2, it should have been test 1). There is a possible bug in the installer. If you have two valid x-aviation accounts, the installer username / password only checks if its a valid x-avation user, it does not check if you have purchased the product you about to install.
So in my case, i ran the installer, used my test 1 credentials, the software downloaded and installed but then of course, it would not validate teh G500 via Gizmo as its the wrong account.
I have asked x-avation to move the G500 to the right account.