React Router not updating (remounting?) a component

https://github.com/aikastor/homework-65

here’s a simple project I’m working on.
The task is to have a Layout with a navigation panel, and content.
There must be only one component to display some data from a server based on props it receives, however, it’s not updating a component when a path changes. I know there’s a fundamental flaw in my code, I just don’t know why it appears.

currently , i have found one mistake which is you are using <Spinner> without creating a component.