Call API - Oracle 11g Release 11.2.0.4.0

I am using the apex_web_service.make_rest_request function:

 L_CLOB := apex_web_service.make_rest_request(p_url         => 'http://192.168.100.210/ARXivarNextWebApi/api/v3/searches'

                       ,p_http_method => 'POST'

                       ,p_username  => c_ws_user

                       ,p_password  => c_ws_pwd

                       ,p_body    => v_arg_var

                       );

with the following headers

apex_web_service.g_request_headers.delete;

apex_web_service.g_request_headers(1).name := 'Authorization';

apex_web_service.g_request_headers(1).value := 'Bearer ' || C_TOKEN_CODE;

 apex_web_service.g_request_headers(2).name := 'Content-Type';

 apex_web_service.g_request_headers(2).value := 'application/json';

 apex_web_service.g_request_headers(3).name := 'Content-Length';