The "auto launch" setting in the VMcast app can be helpful in getting your waiting room TV broadcasts back up and running if your device experiences a power outage or if you are setting up and managing an account with multiple streams or locations.
Install the VMcast app on your Amazon Fire TV Stick.
Once you're logged in and the app is launched, look for the "Settings" option on the VMcast menu screen. If a loop is playing, you may need to press the "Back" button on your Fire TV Stick remote.
Scroll down and select "Auto Launch". The option will change from "Off" to "On".
You can return to the menu screen and select the loop you want to play. Your device is now set up to automatically launch the VMcast app.