In the identity server project, you need to register the client application. This is done in the application's seed. You can add an additional registration apart from the one that comes by default.

On the client side, you should reference the identity server as you’re already doing; however, I noticed that some configurations are not entirely correct.

To enable the client application to obtain the current user’s information, an extra step may be required — adding the scopes in both the identity server and the client — and in the client, adding a claim mapping so that the user information is displayed correctly when you use the current user.