It is fantastic to see that ESRI are monitoring there own forums! I found the problem was change the SingleSign on to false and it worked. Now I am trying to get SSO to work. What a freaking nightmare! Open Source Software, Awesome... not!
For Geoportal Server related questions or discussions, please use our discussion forum on github (where we host geoportal server source code): https://github.com/Esri/geoportal-server/issues
If you want a user to login to their desktop/laptop and then be automatically be logged into Geoportal when accessing it, you will need to configure �??windows integrated authentication�??.