AD FS Server 2012 R2 Question

Hi

I have setup ADFS on 2012R2 with a Web Application Proxy Server (WAP).  I have published 2 apps.  

1. Claims based app - works fine

2. Non-claims app - Kerberos in IIS to a standard website

On the non claims aware app It authenticates fine but just shows a blank page. The URL shows as the web page followed by /?authToken=eyJ0eX........

I have set the WAP to be domain joined as per MS documentation but just can't seem to get the site to work through ADFS.

Am I missing something basic?

Thanks