Can you help debug React code?

Question

React

There is an article Application on React according to which I did everything correctly and everything worked, at the end of this article we connect the bootstrap styles and this is correct for me, but I get an error
. Help solve it.
PS: I searched everywhere, a lot of similar errors on the Internet, but none of them are related to mine

Answer 1

It is clearly written what the problem is. In the Application component, you either forgot to export the component or mixed up deafult / named imports.
Show the Application component code.