A Unity ID allows you to buy and/or subscribe to Unity products and services, shop in the Asset Store and participate
in the Unity community.
Thanks for your feedback it's working. I've launched the plugin in a new project and worked. I just had to reimport my package into the new project.
I just bought your plugin, and I can't make it work on Unity 2018.2.17f1 (64-bit) .
The menu "Window|Unity Fbx Exporter" didn't appear.