Hi, Brett,
do you have an Attach action in your business object? Did you go through Blue Prism Foundation Training? It is covered there. it seems that you are not connected (that is what the message says) to the application. If you want to work without Attach then you have to always launch your HTML application from Blue Prism. Then the connection is created automatically. At the moment when you reset your process the connection is lost and you have to either launch the application again or implement the Attach thing ;).
Regards,
Zdenek