Auth0, Angular and .Net

I think I am missing something simple but I cannot figure out what it is.

I have got an Angular 12 app which allows me to sign in to Auth0 and return users information.

Now I wish to call my .Net API and call an authenticated method.

If I use the const accessToken = await auth0.getTokenSilently(); with my angular app details I get the response www-authenticate: Bearer error=“invalid_token”.

If I use the information associated to the .Net API in Auth0 I do not get a token from const accessToken = await auth0.getTokenSilently();

Any help with this would be greatly appreciated