Granting access to application user

Hi All

How I can create a user and grant access to a specific application in runtime database,

My Apex runtime application on production version 20.2

I was trying to grant access to a user named ABC on application 15 as administrator and contributor

begin

  APEX_ACL.REPLACE_USER_ROLES (

    p_application_id => 15,

    p_user_name    => 'ABC',

    p_role_static_ids => wwv_flow_t_varchar2( 'ADMINISTRATOR', 'CONTRIBUTOR' ) );

end;

When I log in to the application I am getting this error:

You are not authorized to view this application, either because you have not been granted access, or your account has been locked. Please contact the application administrator.