Follow these steps below to successfully stream to Twitch through BoxCast.
Log into the BoxCast Dashboard, and click on Settings, then Integration.
Choose RTMP Destination.
Give it a name (this will only be seen internally).
In a different browser window, log in to your Twitch account and go to Dashboard.
Click on Settings on the left-hand side of the screen and then Stream Key.
Copy this stream key into the BoxCast tab, under Stream Key.
Open a new tab, and go to this site https://stream.twitch.tv/ingests/ . Pick the RTMP URL you are closest to. In this example, we will use "US East: New York, NY" RTMP URL:
Copy the RTMP address into the BoxCast tab under Server URL.
Save Changes. You do not need authentication.
Now you can schedule to stream to this destination when you schedule your broadcast. Simply choose Custom Destinations in the scheduler, and select your Twitch stream.
You're now ready to simulcast to Twitch!