I change the mesh’s world rotation to relative rotation, the problem solved. I remeber in the video he said you need to change to relative. I don’t understand why for now, hope I can understand in future.
Relative I’m assuming is another word for local as to the context.
World is usually a fixed value as to direction. Think of a compass where North will be fixed value for the purpose of navigation.
Relative, or local, is a value relative to the individual joint rotation. For example the root bone starts with a value of 0 degrees you could rotate it by 10 degrees but the attached child joint will remain at 0 “relative” to that joint. If set to world both the parent and child will have it’s rotation value set to to the world.