Hi Sachi,
quick question is your request a manual "call"? meaning did you manually code the web_submit_data or something like that or the authentication call came from your recording? Usually the developer/technical lead of the project can provide you the proper credentials so that when you send it over to their app server it will accept your credentials. Otherwise if you assume your "ldap id" can be used to their application chances are they have to "add your LDAP id" through.
i recommend you ask for the user ids to be used for your testing whether you do recording or manual coding