I tried several things. First deleted all the registry entries for Animation Paper and restarted computer. Then installed again Animation Paper and it asked key and I entered new key. It still doesn’t start, I even tried to start it from command prompt and also checked on Task manager same time when I tried to run it. It appears in task manager and then disappears. So it is like something is missing at start and exits, or maybe memory related. However on my Windows laptop (same Windows 10 pro (1909) with 32GB RAM) it just runs fine, with ~78MB memory usage. It runs fine on his old mac mini with 8GB RAM.
So it maybe related to Windows, either something is missing or something else.
Does Animation Paper write logs or to eventlogs in Windows? Is there anyway to debug it?