If you are having difficulties getting your stream to simulcast try these steps:
A] RESET YOUR YOUTUBE TARGET IN v3
1. Go to YouTube.com and completely LOG OUT.
2. Clear your browser cache.
3. Within your v3 Studio, remove the current YouTube target here:
4. Re-add your YouTube target within your v3 Studio. This should force your to completely log back in to your YouTube account.
Run a fresh test to see if things now work as expected.
B} CONFIRM YOUR STREAM KEY WITHIN YOUR YOUTUBE ACCOUNT
1. Log into your YouTube account.
2. In the upper right click on CREATE > GO LIVE
3. Within STREAM (upper left) > Stream Settings tab (lower left), make sure your STREAM KEY is set to "Sermon Net Reusable Key (RTMP, Variable).
* Watch this video for additional details and follow the steps outlined: