External UI in Human Task activity in PCS instead of webform

Summary:

I am trying to use Oracle APEX page instead of VBCS to build the external UI for Human Task in PCS. But getting error that "refused to connect" error when the Task form is open from the Task list. Even if i give https://www.google.com as external UI link also I am getting same error.

Content (required):

I am trying to use Oracle APEX page instead of VBCS to build the external UI for Human Task in PCS. But getting error that "refused to connect" error when the Task form is open from the Task list. Even if i give