As stated in the Testing and Publishing section of the documentation, you need to first do account linking through the Google Assistant application on your phone. That associates your Google account, and your Google Assistant, with an account on your smart home server. Once that happens, you should be able to use the simulator to make authenticated requests. Before that happens, there's no association and so a request cannot be made.
It should also be mentioned that the way to invoke and use smart home actions is different from a standard conversational action. With a conversational action, you may enter into the simulator "Talk to Number Genie" to invoke your action. With smart home actions, commands are given as one-off queries. There is no "talk to my smart light". You instead will be able to directly enter "turn on my light".