I've been running SN8 Pro Plus on several machines, iMac, MacBook Pro and Windows 10 computers. I even have SkySafari 6 Pro on my iPhone 10 and iMac. All of my computers sync with LiveSky except the Windows 10 64bit laptop. I just upgraded to LiveSky Premium to see if that would help, no luck.
I have uninstalled SN8PP a couple of times with no change.
I can add items in SN8PP on Windows 10, and they flow to LiveSky then they disappear from SN8PP Windows. Nothing added to LiveSky or via my iMac flow to the Windows laptop.
Here is a screenshot from SN8PP from my Mac: