VBCS Custom Authentication Page

Summary

How to redirect VBCS app to a custom login page ?

Content

Hi, 

How to redirect VBCS application to a custom login page if the user not authenticated before and what should i do to authenticate using IDCS apis then redirect normally to VBCS app ?

Note : I'm using PCS rest api in VBCS , that's why I need to be authenticated to retrieve each user's tasks

I followed up this tutorial : https://www.oracle.com/webfolder/technetwork/tutorials/obe/cloud/idcs/idcs_authn_api_obe/authn-api.html

And yes I'm authenticated but user's tasks cannot be retrieved and I got the message Unauthorized , I think I'm missing something.