Outbound web service call from oracle proc fails with 401 - Unauthorized: Access is denied due to in

Hello folks

I have a code which calls external Web Service from Oracle Proc. it fails with "401 - Unauthorized: Access is denied due to invalid credentials".  Same WS thru browser works fine when we pass userid and password.  it is calling IIS web service where authentication is set as windows and basic.

set scan off;

CREATE OR REPLACE procedure SMDB.PRC_EWF_TEST_WS

AS

  v_guid varchar2(100):='{542ECE99-4FC4-44E7-B455-EA51D9E988BF}';

  v_user  varchar2(20):='C0004793';

  req utl_http.req;

  res utl_http.resp;

  v_url varchar2(4000) := 'http://workflowservicesdev.local.domain:8080/workflow/AddAppInstance';