Due to the authentication used in the application being tested, I have been using the WinInet option to run my scripts in VUGen and that is how I get pass the authentication part when recording and running my scripts. However, in the controller the same script gives me the following errors: vuser_init.c(27): Error -26630: HTTP Status-Code=401 (Unauthorized) for "https://......" and vuser_init.c(27): Error -26547: Authentication required, please use web_set_user, e.g. web_set_user("domain\\user", "password", "hostort"); I call support but their different suggestion have not worked, according to them if the script is run successfully by VUGen, then if the setting are the same script should run in the controller.