When i scale my mesh my shadows disappear. Why this is happening?
And what is the best way to make shadows softer?
I found that scaling mesh helps a lot to control how soft are the shadows but i think that is not the best way 
Hello, how are you?
Well, this probably a lighting build issue. If you are using Static Light, whenever you scale or move your meshes, light needs to be rebuild. To do so, you need to ‘‘Build>Build light only’’. That probably will give your shadows back.
There are different ways to make you shadows softer, it can be via the Lightmap Resolution, you can increase its number to get better shadows, and also, with a Post Process Volume, you can tweak some stuff.
Let me know if this answers your question.