Crashes on new maps

Hi

I tried creating my own HOI4 map using MapGen v2.2 but HOI crashes when trying to load my map mod. I then downloaded this blank map: https://steamcommunity.com/sharedfiles/filedetails/?id=1356703754 But the game crashes also while loading that.

Then I tried copying the default map to my map mod folder and this works!

So my question is how to get started at HOI4 map modding without crashing (which files in map are essential)? And if I want smaller map what sizes are known to work?

thanks, all tips welcome!