Unable to view App when acessed using HTTPS

I have a News Feed App (http://ift.tt/1Jt1NqE) configured and working on my SharePoint 2013 Site. However when I try to access the use using HTTPS;

• Nothing shows - where the app normally appears is blank white. All other items on the page work correctly (only this app is having a issue)


• 
  

  When viewing the page source the following appears where the app should be:

  
  

  
  <script type="text/javascript">
               var gearPage = document.getElementById('GearPage');
               if(null != gearPage)
               {
                   gearPage.parentNode.removeChild(gearPage);
                   document.title = "Error";
               }
  </script>
  
  



• 
  

  Similarly when trying to access the app page (I.E. http://ift.tt/1zrUEgh) I am presented with a blank page. Viewing page source reveals the same JS script as above. Again this works fine when access using http

  
  


• SSL cert that covers the app site has been implemented


• I am using the latest version of the app

Any ideas?

Cheers.