Web driver not holding conversations

Hi all,

sorry if this is me being ignorant of something obvious but for some reason i'm not able to get a continued conversation using web driver. I get a success response, my conversations start fine and give the first response, but unfortunately when i respond with an assumed response in a conversation it doesn't recognize the response and in turn acts like there was no intial conversation, even maintaining the userId in my call. I'm using postman and sending 3 params; userId, message and driver=web as in the instructions. Any thoughts on where i can start troubleshooting? Web widget itself works fine and responds as it should... is there a cookie i have to stash locally?