If the client and the Secure Token Service provider are hosted on 2 different domains, the
X-Frame-Options HTTPS header needs to be set to allow all iframes. Once set, use the CSP HTTPS header to only allow the required domains.
The silent renew requires this.
Add this header to responses from the server that serves your SPA:
https://localhost:44318 is the address of your secure token secure server, i.e. the authority which issues tokens.
E.g. if you use nginx to serve your Angular application, you can configure the server as follows: