Complete OpenID Connect authentication with PKCE using iframe (no page redirects)
Configure your Okta environment settings:
https://dev-09210948.okta.com
https://dev-09210948.okta.com/oauth2/default/v1/authorize
https://dev-09210948.okta.com/oauth2/default/v1/token
https://dev-09210948.okta.com/api/v1/authn