Finally a working solution.
The problem was as @Hardcawcanary indicated. After removing the Streaming (World Settings -> Enable Streaming = False) and also removing all Data Layers (Data Layers -> Select All -> Delete Selected Data layers), the ability to Launch and Push works.
I re-added in the Data Layers and found that one of the DataLayers was corrupting things too, so I just deleted it and started that one again.
If I ever change back to Streaming - it fails. I have tried deleting the HLOD and creating a new one, but no luck. So for now I am keeping this off as it really doesnt impact my map.
Thanks all.