ID3206: A SignInResponse message may only redirect within the current web application: ‘/’ is not allowed
This one happened when I started working with doing redirects. There are two different ways to do redirects in Identity Server. 1) Define it in the admin configuration screen. 2) Passing a web (url querystring) parameter for the redirect.
This error occurs when you try to do both and the addresses don’t match. The web address in the admin config screen is considered to be “the current web application”. In other words. In a disagreement, the admin settings will win. Anything you pass in the URL has to be very close, or an exact match. Otherwise, you will see this error.