Which Authorization Server is my application using?

I am unable to figure out which Auth server our application is using.

I am using OpenIdConnectAuthenticationOptions. The Authority value is set to our default OKTA url.
The value is https://.okta.com/. Since the oauth2 value is not specified, is it using the default Authorization Server? Is that is the case, where can I get that value?

If the issuer in your application is set to just your Okta domain AND, if you parse out the tokens being returned by Okta and see that the iss value is the same, then that means that the Org Authorization Server is being used.