I am trying to get https://developers.arcgis.com/javascript/jssamples/portal_oauth_inline.html to work on our own web server. Everything works fine in Chrome after I changed the portalUrl to be the one for our organisation, but it doesn't work in Internet Explorer 11.
I do get a successful login but the result page shows a blank page.
In the Console I get this error:

I have tried to use the resource proxy, but that gave me a syntax error because the response was HTML instead of JSON.
Hope you can help me out.
Regards Jonas