Categories and child categories don’t work

Hi!
I have a problem with my product categories. I can create them, but then they just disappear. I can make them appear again if I click on the “name” button in the categories list.
But my real problem is now. I am trying to create child categories to organise my shop, but when I make a child category and add the parent it doesn’t work. Is like woocommerce doesn’t remember it once I change the window and the child category disapear.
I have tried to fix it taking off all the plugins but it isn’t working yet.
I don’t know what else I can do.
Can someone help me?
Thanks