post-redirect? not working or Preflight response is not successful

[zendevil]

I have the following code:

defresource handle-sign-in [redirect-uri]
  :available-media-types ["application/json"]
  :allowed-methods [:post]
  :post! (prn "welcome to post")
  :post-redirect? (fn [_] ;;(ring-response
                           {:location redirect-uri}
                           ;;)
                    )
  )

When I send the request, I get the errors Preflight response is not successful and XMLHttpRequest cannot load [authorize-uri] due to access control checks.
When I wrap the redirect location map around ring-response, however, I don't get the errors but neither do I get the redirect. What am I doing wrong?